Same problem here. Have Ubisoft+, neither Watch Dogs Legion nor AC Valhalla launches, while AC Odyssey works flawlessly.

Same here :( , Origins and Odyssey works but not Valhalla. Block on Splash screen.

Guess we'll need to wait for Glorious Eggroll to pick things up, possibly with newest proton 5.13.

Yes, Proton-5.13.2-RC3 doesn't fix things. Apparently VKD3D-2.0 is missing some calls, so does WINE (i.e. with regards to Speech API -- patches have been created, but not yet merged). Work needs to be done. There's currently no technology on the planet that will allow to run AC:V natively on Linux. Work is in progress.

do you think valve is helping with this, or do they dont care since ubisoft left steam

TL;DR: we just need to be patient and wait.

While this should be taken as an educated guess and nothing more, my take on this is as follows:
DX12 is inevitable. Support for it on Linux infrastructure is currently lacking, but improving each day. AC Valhalla will most probably come to Steam one day, because Steam is too big to ignore in the long run, and even if it won't, Valve is committed to Linux support and they'll want to use DX12 bells and whistles in their games under Windows sooner or later, while also keep them playable on Linux. We, the Linux users, are also no longer ignored in promotions like free games included with CPUs/GPUs, as there are promo-redeeming tools for Linux offered at least by AMD, and it's silly to give someone a gift that they can't use of. This is clearly the case with AC:V, that's offered by AMD to Linux users, yet they can't play it as of today: if you got AC:V from AMD, e-mail them and ask when will you be able to play it under your OS of choice. I think group of people that want to, yet can't/won't play new games on Windows is growing. There are also IOS users, which by themselves also put multi-platform support on the radar: if you have to support something else than Windows anyway, then why not also support Linux while at it? VKD3D-proton, while not targeted at AC:Valhalla, is under active development and it's primary goal is: "The project serves as the development effort for Direct3D 12 support in Proton." -- https://github.com/HansKristian-Work/vkd3d-proton

Oh, and there's also the fact, that apparently AC:V is not a crap game, and someone with knowledge and free time at their hands will set a goal of playing it under Linux, even if only because they can. :)

All that being said, I hope that AC:V and other new games support will come as an accidental result of ongoing work, as it should be. Holy grail-level state of things is Linux's compatibility with proprietary platforms that is reachable easily enough, so main game publishers will deem it as a worthwhile effort to just account Linux support during development instead of leaving things to community after release.

To do my part, I myself have a gaming-viable PC, yet I refuse to play games under Windows because someone has to. I could dual-boot, I could try to do some virtualization; I could go and buy a dedicated GPU only for PCI pass-through to Win10 VM, or I could buy a PS5, but I won't. Meanwhile I've cancelled my Ubisoft+ subscription and will resubscribe once there's a point to. I urge everyone to do the same: don't buy Ubisoft games on other platforms and wait until Linux support is announced either by Ubisoft or players reporting success. Unfortunately times are like they are; games are no longer developed out of clear passion; it's a business - and like with all business, you have to vote with money and patience in this case. Ask for Linux support on Ubi's support channels, so they know that it's no longer optional.

Quoting: OfcaValve is committed to Linux support and they'll want to use DX12 bells and whistles in their games under Windows sooner or later, while also keep them playable on Linux.

I don't get this part. Vulkan provides these same bells and whistles on both Linux and Windows (among other platforms), and several games by Valve support Vulkan already (via the Source 2 engine). I don't think Valve is planning to use VKD3D for their own games on Linux.

Or did you mean something else?

Quoting: tuubi

Quoting: OfcaValve is committed to Linux support and they'll want to use DX12 bells and whistles in their games under Windows sooner or later, while also keep them playable on Linux.

I don't get this part. Vulkan provides these same bells and whistles on both Linux and Windows (among other platforms), and several games by Valve support Vulkan already (via the Source 2 engine). I don't think Valve is planning to use VKD3D for their own games on Linux.

Or did you mean something else?

That's a moot point then with regards to Valve's own games. That being said, more and more games offered via Steam will require DX12 and Valve will want them playable with Proton for sure. This should make AC:V playable even if it's not one of those games. VKD3D-Proton repository could be interpreted as "we are not happy with progress being made by Codeweavers, and it's time to speed things up with our own hands". It's a hard fork with no compatibility plans. This isn't necessarily a bad thing; in the end we want to play games, and it isn't much of a difference to experience whether I choose wine, lutris or proton as a runner in Lutris as long as the game runs well.

My point being: Valve's work doesn't only serve Valve, which is an unfair worry that I hear a lot lately (i.e. "AC:V is not on Steam, so don't expect it to run on Linux anytime soon"). I mostly use Glorious Eggroll's take on Proton ( https://github.com/GloriousEggroll/proton-ge-custom ) in Lutris nowadays -- Valve gets nothing out of such use; in the end only Ubisoft benefits from it, as I use Lutris' and Valve's product of labor to pay for and play Ubisoft's games. That's why I'd love to see EA and Ubisoft tossing some man-hours and/or money into Proton, or at least make an effort to make things "just work" with Proton. It's not that they need to pay any licensing fees to get money from Linux users. It's a free platform to support and get more customers. But: happy thoughts. few years ago we had no Proton, no Linux support on Steam, no native drivers. Things are only getting better here.

Someone on youtube described how to run the game from different drives. It seams to depend on finding video and sound folders on C: under Windows 10.
The behaviour was exactly what you describe: it hangs at the login Logo screen.
Maybe this helps and you can figure out some workaround applying this in Linux.

https://www.youtube.com/watch?v=k_z8JMzZ-Hs

But the game needs more time to be patched anyways.

AC:V works with the newest wine-tkg. Running directly from Ubisoft Connect. May possibly need to compile the latest VKD3D-Proton, but I believe that wine-tkg includes that. I had some initial performance issues, but disabled vkd3d logging and now it runs pretty well.