Betta Fish: Betta is sick and I would love any advice on what to do to help him. Thank you!

Tank size: 10 gal

Temp:80

PH: 7.6

AMMONIA: 0 ppm

NO2-: 0 ppm

NO3-: 0 ppm

Food: frozen blood worms and Ultra fresh Betta pro shrimp patties pellets. I do blood worms not as often as the pellets. Pellets usually 4-5 a day total. Unless I do worms that day then about few worms and like two or three pellets.

(Apologies I’m not really a great tank scaper so the tanks not that aesthetic or pretty)

I cycle once a week %15-%20. I syphon the sand/ dirt for nasty poos. I fill the tank back up with my sink water, I use prime and wait for it to be room temp before adding. I got the parameters from a API fresh water master test kit. I do have a filter. I believe he has fin rot and has tried to help it with stress guard and kanaplex so far. Only two doses in of kanaplex. Before that I tried API Prima fix fungal infection treatment, but he wasn’t getting any better so I thought the kanaplex would do a better job. I’m hoping it’s not spreading to his body but his color is getting a bit dimmer on his scales. I feel so bad for my Kipper (that’s his name). He still has a good appetite and swims around a bit. Definitely less than usual. I just need some guidance on what I may be doing wrong, and what I need to do to fix it. I’ll literally do anything he’s my son! Thank you for any advice in advance. Please don’t hesitate to tell me if I’m messing up in anyway.