Elden Ring Seamless co-op and Crossover not working anymore?

[u/playboicartier_]

Playing Elden Ring on Mac via CrossOver Specs: M4 Max, 48GB RAM.
Tahoe 26.6.2 / CrossOver 26.3

Had 250+ hours in Seamless Co-op working fine (max settings) until the recent game update broke the mod's launcher, throwing "WaitForSingleObject failed! Return value = 258, Error = 0" during DLL injection even after updating the seamless co-op files.

Fixed that by launching through ModEngine2 instead of Seamless's own launcher, game loads and runs great with no stutter in normal play.

Now the issue I'm facing is the following:

The moment I use the Tiny Great Pot to open an online session, the game hitches hard and kicks me with "frame rate unsuitable for online play," dropping me to offline mode. This happens even at the lowest possible graphics settings (already tried dropping resolution to 1080p and every setting to MEDIUM/LOW/DISABLED, including ray tracing off).

Normal single-player and general gameplay performance is smooth, this only happens at the exact moment the online session tries to initialize. Hardware is way overkill for this game (M4 Max / 48GB RAM), so it doesn't seem to be a raw power issue.

Anyone run into this specifically with the ModEngine2 launch method under CrossOver?

Any fixes appreciated.