Betta Fish: Help – Sick Betta

Hello everyone, I’m coming here hoping someone might have an answer. This is wordy, I’m sorry.

I got this Betta (his name is Glintstone) in December from my supervisor at work because her family bought it as a “funny” White Elephant gift that, surprise surprise, no one wanted. Pretty sure he’s from PetSmart.

He came with a 3 gal tank + supplies but I eventually switched him to a 10 gal with live plants in January. I introduced a few neon tetras and ghost shrimps in the tank and everyone was doing amazing for the first three weeks. He’s a very friendly guy, didn’t bother the other fish at all, and would be very curious and energetic.

Well, almost two weeks ago I noticed he was acting different. One day he was his usual self, and the next he was lethargic and would barely eat. The ghost shrimps disappeared, too, and this is what I think happened:

The shrimp nipped at his tail (I would feed them a shrimp tablet once every couple of days so I thought they were eating them, even through I almost ever saw them because they’d hide), injuring him, and Glintstone ate them out or retaliation/aggression.

The tail injury turned into fin rot that I noticed about a week and a half-ish ago, got Melafix (which I later found out can be even *worse* for fish, ffs) and started treatment Monday. Tuesday he instantly got worse: chunks of his tail went missing and he started refusing any food. I switched to KanaPlex on Wednesday + aquarium salt + Indian leaves, he developed popeye (to one eye at first, now both) on Thursday, I gave him the second dose today, and today he has pineconing on his head.

And now as I’m looking at him I see he has some white around his face but idk if it’s Ich or something else? I don’t know what else to do and he’s just not getting better. He hasn’t eaten in almost two weeks and all he does is lay at the bottom of the tank and just comes up for air every now and then. He’s been quarantined back in his 3 gal tank and I’ve done water changes every day while he was on Melafix, then every other day when I started KanaPlex.

Any advice is welcome, I’ve been stressed out and sick to my stomach seeing him look like this. I can’t afford a vet and I’m honestly debating euthanizing with clove oil, but only as my absolute last resort. I just feel like this all developed way too quickly in just one and a half weeks and I feel like I’m scrambling for every possible cure but he’s not showing ANY signs of getting better. I don’t know if I’m just impatient but I think after a week of being on Melafix and now on his second dose of KanaPlex, he should show signs of being better, no? Water parameters in both tanks are great, no issues with water quality.