Add keyboard and mouse to Xbox and PS4 (and when you plug in your keyboard and mouse it automatically places you with keyboard and mouse players so it's fair) : r/apexlegends
How to Play Apex Legends Keyboard and Mouse on PS4 - YouTube
PS4 Gaming Keyboards | PS5 | SteelSeries
XIM APEX Mouse and Keyboard Adapter for the PS4 | Endgame Viable