http://bugs.winehq.org/show_bug.cgi?id=57456
--- Comment #10 from daniel daniel.penalized@proton.me ---
Secondly, besides this issue (the lack of window centering and a black background), I believe that the resolution scaling is also not working. I mean, even when I apply this workaround, the games internal resolution doesn't seem to change, so the game remains at a lower resolution. This is easily visible in Splinter Cell 1, with this workaround, the graphics are visibly lower compared to the graphics when I change the game's resolution in the settings. This could be another issue, which probably needs to be opened as a bug report, but neither of these two issues happen with this MR: https://gitlab.winehq.org/wine/wine/-/merge_requests/5057, which makes me assume that the two things are correlated.
And that's a mistake on my part. Not even in winex11.drv is the game's internal resolution increased (and, consequently, the graphics improved). However, even when labwc implements window centering and black borders, it still won't be like it is in X11. In X11, old games are filled to my monitor's resolution, so there's no black border. This MR (https://gitlab.winehq.org/wine/wine/-/merge_requests/5057) for winewayland.drv works perfectly the same way on X11: the game is scaled to my monitor's resolution, without any black borders!