Dont know exactly when they enable EAC for Proton but I was playing this game for more than 30 days without any issues. Clip from yesterday https://spectra.video/w/qW8S2J6qM9YqS6v4kPomZX
https://ayaneo.com/article/806
Here is from their website which also says “AYANEO NEXT LITE comes pre-installed with the SteamOS gaming system for the first time”.
Video where he talks more about Steam Deck
Also presentation is available on Youtube starts at 4:12:05
What app is that? Maybe try opening in browser video link
I thought it was interesting that in system requirements says Proton for Non Native game