PROTON_PULSE_LATENCY=60 PROTON_FORCE_LARGE_ADDRESS_AWARE=1

Also used tasksel to set CPU affinity to utilize all but 2 of my CPU cores for this game.

ALT+TAB to other windows does stop controller input, replugging the controller was my workaround.

There are dramatic frame drops every time a new scene loads (Walk into a new map location or transition into cutscene). I installed the FF13fix files from a previous report: https://github.com/rebtd7/FF13Fix . It signifcantly improved performance. The framedrops are still present and noticeable, just not as dramatic.