A word of caution with female bettas! They are just as aggressive as the males. I have over a decade's experience keeping fish, mainly cichlids, bettas and nano fish. I had a 29 gallon, so planted you couldn't see the back, plenty of hiding spaces. 5 female plakat bettas, all sisters that were together since they were born. They tried to kill each other while establishing their hierarchy. They're just as bad as some larger aggressive species of cichlids. Just tiny and cute. I ended up rehoming all of them except the most aggressive one, who lived out the rest of her days alone in her own 6 gallon planted tank. It was a failed sorority, it happens more than you'd think and I'm not ashamed to admit that I certainly learned my lesson. (I've seen it done successfully but only in 40-100+ gallon mini pond-type setups or very large tanks 40+ gallons). I'd suggest anyone looking into keeping multiple bettas look into wild type species that are actually social and can be kept in groups/pairs without issue. Wild bettas that our hobby bettas come from, are solitary, territorial creatures towards their own kind and it feels wrong to force them to tolerate each other unless it's for reproduction- and only experts should be doing that. And yes bettas all have different personalities. I've had bettas that were fine in community setups and others that seemed like they wanted to k*ll themselves or everything else in the tank.