Hi! Welcome to the community!
If you have had Betta in the past, you know not all Betta fish would like living in a community tank. Especially males it seems, and but even some females will be tankmate killers. Even seemingly with things going alright for quite some time then one day there is a massacre. Perhaps as the fish grows into maturity?!?
With that amount of room and not over crowding you have a better shot.
Think nano fish too since you might like a group to shoal. If you are sharp you might be able to ID the different ones by M/F or color identifying secs, etc.
There are usually available at the lfs
dwarf Pygmy Cories /Corydoras Pygmaeus, which are adorable and reasonably priced. Which would be a great option for that sized tank!!!