Feeling discouraged, are we doing something wrong?

Our baby girl Pearl died today. She was fine, ate, swam, interacted with us, all as usual, and then the next day she was all pineconed. We tried epsom salt baths and medication, but it was clear she is suffering and only getting worse, so we put her to sleep.

This is becoming too much. It's been a year and some months since we joined the hobby, and we've buried 3 bettas already. Always the same thing. 6 months in and they get dropsy out of the blue with no prior symptoms or anything being wrong at all. Pearl made it to 7 months and is officially our longest living betta.

If it weren't for the shrimp and other fish we keep, I'd really believe we're just shit at keeping fish alive I guess and drop the hobby! But literally no one else is dropping like flies other than the bettas. We've got pygmy cories, kuhli loaches, ember tetras, chili rasboras, celestial pearl danios, and a colony of shrimp that we started at the same time we got out first ever betta a year ago. Most of the other fish we also got around that time, maybe half a year in.

What is going on?? Is my boy Tilikum next? To be fair, they (the bettas) all are from the same place which I am now convinced has a shit source. There also don't seem to be any breeders in the whole country, or at least none that I can find through Internet. There's a fb group, but it's mostly dead the last year or two or three.

But like....has anyone else dealt with a streak as unlucky as this? At what point do you just give up and move onto a different fish? We're considering scarlet badis for the 20g now.