Betta Fish: Please help. Fuzz hasn’t improved

please help

I’m so new to this and trying so hard to be good to these guys but things keep going wrong.

My poor guy was doing so good and now he’s gotten this fuzz.. (the last photo shows what he looked like last week. Sorry about the red tint on the photos the white balance is weird)

The other one I got had a fuzzy disease (not sure if bacteria or fungus. The pet store said fungus but looks like pictures I find of columnaris) . That fish is and has been In a different tank than this one. I treated it with sulfaplex and aquarium salt and almond leaf. It had a noticeable improvement after 2 days and after a week and a half completely gone.

I noticed on Saturday or Sunday morning, that this guy had some fuzzy looking stuff hanging from his chin. (It’s a little different than the whisps the other had on his side. Not as white looking and more loose looking)

He was in a cycled planted 5 gal tank with a snail that I had just moved him into a week prior. So put him back in this smaller 1.5 gallon tank as a hospital tank. I added 1 tsp aquarium salt and a dose of sulfaplex(it’s hard to dose this small tank because the instructions are for 10 gal 2-3 scoops so did 1/3 scoop. It looked like he was getting better after a day, the medication says to re dose after 3 days so I did that yesterday but he seems to be back as bad or a little worse than when he started.

The treatment worked so well for the other fish so I don’t know what to do.

It’s not a cycled tank because it’s the hospital tank so it doesn’t have ammonia nitrates or nitrites. It’s heated and has a bubbly sponge filter the ph is a little high at 7.6/7.8. I didn’t have any new almond leafs so maybe I messed up because I washed and added a small mopani wood from his big tank and some oak leaves (several people in r/blackwater have used these )

I was going to to back to the fish store (specialty store not petsmart ) today for but I locked my damn keys in the car so I have to wait until my ex brings my kids tomorrow morning and unlocks it for me.