Connected Ethernet now WiFi is terrible

Trying to improve speed and internet stability throughout the house. We have four people on zoom all day with virtual school and work, plus tons of entertainment devices and speakers etc. Connected Ethernet Cat 6 cable to switch and brought Ethernet to a PC, appleTVs, Xbox, Sonos, etc. Ethernet seems to be working well but now WiFi is awful. Rebooted XFi Gateway numerous times, restarted devices, no improvement. Help!!!