Is there Some way to get plugin worked on os 3.5.(17) ?

Hello sir! I stay on SteamOS 3.5 version, which is pretty stable (even nowadays) and has 2 sliders for hz/fps lock. Other components proton and etc are up to date. Its cool and stable mostly for my old games teerlist but sometimes for newone I want to increeese fps so I tried LSFG plygin. Sadly, its not working for me at all.. As I try to multiply the fps by any amount, the fps counter doesn't change. I have tried all the available workarounds in the options but nothing seems to work. I've tried reinstalling decky, the decky plugin, the lossless scaling app officially bought with steam. In plugin settings looks good, everythings lights green. Plugin says game (by actual name) is running. In plugin settings are: 2x Flow Scale: 80% • Base FPS Cap: OFF • Present Mode: Mailbox|vsync (default) • Performance Mode: ON I have changed it to linux_testing and deault and done many variations.. My question is - is there some way to get it worked on os 3.5.(17) may be with some extra lounch options? The games I'll try to run - every installed games old and new, but my goal is to increase fps in newest Arc Raiders Thanks, Kudos!