I looked to see what I could find. So far besides what you have already done I found these to check.
Make sure airplane mode is off, see if the messaging app needs update, check for software updates, make sure SIM card is seated properly. Network issues.
There's a video on Youtube that may help. Search [SOLVED] Samsung Galasy A54 Can't Send/Receive Text Messages
Hope you get it figured out what a pain. When I searched looked like people were having the same issue last year.