ok so,

you cant host your own telegram servers.

and you dont have any privacy guarantees from them if you use theirs.

SimpleX cant read your messages,

by design.

even if you're using their infrastructure.

telegram can.

and you can always run your own Simplex relays.

SimpleX messages are always encrypted.

Telegram has option encryption in a closed source context.

these are big differences.

but sure i guess, don't use it because Russian people.