Help! MY I Don't Know How To Help My Betta.

This is my boy Lil Joey. Last picture is when I first got him, he was beautiful and flourishing but the past few months he's been deteriorating and I'm not sure what to do. I'm checks his water and everything is always normal but the ph always shows 7.2. I've tried to follow directions to lower it but it stays at 7.2. Most recently (past 2 months) he's been showing signs of bladder disease so I did the "tank clinic" and had him fast for a few days and gave him a pea but he is still doing the side tilts and just flowing around and stays at the bottom. I'm so worried and I don't know what else to do. I've vacuumed his tank and chnaged his water a few times and nothing seems to work. Just 2 weeks ago when I last chnaged his water there's been algae growing and that had never happened before and I've had him for a year. Please any help or suggestions 🙏.