Betta Fish: New Betta Transformation

TLDR: questions about care at bottom

Hi everyone, got my first Betta as an adult. I was intending on getting him from a big local owned spot near me (that has much better quality fish care), but I grabbed him from another far less reputable spot near me. I wasn’t intending to grab him, but he was about to be walked to the flusher because the store was convinced he was passing. I was able to talk them down to pennies to walk out with him. He immediately took to exploring once placed in the tank.

Some notes about his tank.

Cycled for 4 weeks before purchase.

All levels are solid but general hardness has been difficult to reduce.

Only plastic piece is PVC pipe for cave exploring. Edges were all sanded for smoothness.

All plants are real, with pothos, Thai con monstera, and monstera deliciousa roots only in the water.

Sponge filter and heated at 79F.

He will be upgraded to a 14 gal tank eventually once I’ve safely cycled it (woo just picked it up yesterday!). I’ll be adding more plants including a huge pothos from the top with really long and beautiful roots, and will be doing an open top setup. With some immaculate driftwood I got. Included in pics. He will get some shrimp buddies when it’s safer in the new spot.

Any and all advice is welcome! I’m new to fish but I LOVE plants and have always loved hardscape aquariums. I just wanted to share his color transformation. His diet is brine shrimp in the AM and pellets PM.

Questions I have

-How much do we feed our Bettas?

-any advice around hardscaping open tops (it will be my first one)

-any preventative solutions to use for plant and fish longevity?

-how to prevent wood molding in open tops that doesn’t include springtails?