yeah bettas arent too gentle on the plants. it doesnt help that your substrate is probably a bit too large in particle size for the roots to really penetrate well.
for the diatoms, there isnt much but manual removal from the glass, frequent water changes, and possibly algae eaters. amanos or otos (though i dont advise having a school of otos in a tank that small).
Thanks for replying Marko! Yeah they definitely aren't, hah. But only a few plants have floated up the rest seem okay and he has finished the initial days of exploring the tank. So I don't think he will be trying to nestle in the plants as much anymore. Because he has already found a sleeping spot.
I've decided to tie the Anubias that have floated to rocks and then if others float I can tie them down as well.
Now that I don't have to worry about that, I can either add Amanos of Otos. I have other tanks I could rehome the Otos Into once the algae is mostly cleared. So I could do Otos. But I could also do Amanos. Anyone know which is better?