Trouble with sonoff working

Hello i have spend a lot of time reading about different firmware, device handlers, apps etc and i am still having trouble.

I have some sonoff basics and shelly’s flashed with tasmota (6.2.1) i used in HA but do i need another tasmota firmware?

What device handler is the way to go?

Do i need the sonoff connect app?

Have a nice day.

Jacques