Hi there. I will try to test this later on linux when i have time.
In the mean time can you check if anything changes when you make a file called dxvk.conf next to the games .exe and insert
d3d9.floatEmulation = Strict
To verify that the game picks up the conf file you can also add dxvk.hud = 1 and check that the hud shows up ingame.
I've added dxvk.conf to the game folder and the DXVK HUD does appear.
The particle effects reappear with d3d9.floatEmulation = Strict, as well as when set to True and Auto. According to the log, it looks like that value was being set to False without dxvk.conf.
Thanks for testing.
The current value is to work around issues in the game from the days of yore https://github.com/Joshua-Ashton/d9vk/issues/292
But back then strict wasn't a option so we just need to verify it doesn't regress anything else.
I will check it out here later on Linux/windows when i have time. You are ofc also welcome to report anything odd you notice when playing with it set to strict
Can't reproduce:

Can reproduce here.
This was with proton 7.0-3RC, amd R9 380 and mesa 22.1.1
DXVK

WINED3D

Edit: Tho it does not reproduce if i select proton 7.0-2.
Can you try #2677? You can find a build here: https://github.com/doitsujin/dxvk/actions/runs/2477933077
Please make sure it doesn't bring back this issue: https://github.com/Joshua-Ashton/d9vk/issues/292
@TBirdSoars May i also say thanks for a nicely made and filled out issue.
@K0bin I'm not getting that issue with #2677. I've heard of that issue before, though I've never personally encountered it. I could be wrong, but I thought that issue was GPU-dependent, only occurring on systems with integrated graphics. It should be fixed for anyone using the SA2 Mod Loader: https://github.com/X-Hax/sa2-mod-loader/commit/13d518555ca3c77311ad13923cf4a909bf868e5f
proton 7.0x1 2022-06proton 7.0-2x1 2022-06
Some particle effects are missing from stages in Sonic Adventure 2 when using DXVK, such as the smoke effects at the start of the stage "Iron Gate":
Without DXVK:

With DXVK:

Software information
Sonic Adventure 2, Steam, 32-bit, D3D9, Windowed, 1280x720
System information
Apitrace file(s)
https://mega.nz/file/bOJDjK5b#PhHebE2q_OuGQUBuBX7oQunqoMczGL2tSiDjtJlt95M
Log files
sonic2app_d3d9.log