I'm sorry that happened to you. I developed mutism after being shunned during adolescence, it took me a while to pick up on social clues and learning how to dissimulate again. I downloaded and read a lot of books (for free, I only skimmed some of them) trying to find answers to my problems. Not sure how much this advice will help you:
-It's better for people to tell you to tone down your voice than the opposite.
-Take care of your posture, clothes, haircut, hygiene and ¨the way you carry yourself¨
-Record yourself and do voice training, I developed a lisp around that time but it is treatable and there are tutorials online on how to fix these issues or make your voice deeper.
-You might have a resting bitch face (hate this term so much) that may scare people, there are also guides on how to look more ¨cheerful¨. This is common for autistic people too. Mewing isn't a meme either, it can help even if you're older.
-Try lifting and not being fat for obvious reasons. You can buy a pair of dumbbells or do basic calisthenics at home. This can also help you have something you can be proud of and not feel so insecure among others.
-Socializing is complicated and I can't help much. What I do is try not to not be self conscious or apologetic when I don't have to and pick up on subtle social cues and microexpressions on people's faces. I'm not autistic but I believe everyone can learn how to do that.

Their ¨love¨ and compassion isn't fake, it's pity. No matter who you are, being pitied when you didn't ask for it isn't a good feeling, it makes me feel like a dog and they don't like you the moment they are able to see you as a human with flaws who isn't innocent. My advice is superficial because I got shunned for superficial reasons, puberty came late for me and it made others not want to get to know me. I don't like people I can't talk to. ummm... I dunno I'm far from perfect, not sure if I should be giving advice to be honest.

I've also had the mutism spell casted on me.
Too many bad social experiences conditions you to avoid socializing, to lessen the pain in a way.

I don't like leaving the house much, but i'll try to aim for a 30 min walk daily to stay sharp.

I can't help you much, as I too need assistance.
Ganbare !

I don't have mutism but i do have a speech impediment that people would make fun of me for. it made me not want to speak for a long time, and i remember taking speech training to help me work on it but i was stubborn and didn't listen most of the time. that was a big regret cause now that i have a job my co-workers are expecting me to talk more. what i was taught was speak slowly and take your time, people are more patient then you think.

>what other people even want from me
Depends on context. Often "Yes, that's cool" is all they want.
>I'm afraid to push boundaries
What boundaries?
>saying nothing is also wrong
Silence is the always winning strategy as long as you're not deaf.
> When they're nice to me I assume they're lying
Don't assume anything.
>When they're cruel it seems like they're being honest.
Let nothing seem to you.
>Their love has always been fake
Wrong.
>their hate is real
Wrong. Their emotions are context driven and can't be considered either real or not. You can't reliably identify when they are faking or not. It's the same as with being sometimes upset and sometimes glad. It's just there and means nothing.
>I have a fear of being seen
Disown it, then.
>I just want to feel the love of another human being.
You have three routes. Read some books on etiquette and learn to be what they love and as long as you maintain the facade, they will love you. Another route is contemplating love, learning to love yourself, the world and all other people, then finding somebody as capable. The third route is understanding that the first two you will never achieve and just accepting the world as it is and not bothering; you can also put love in your acceptance of things the way they are, if that works, you're gonna receive good deal of independence. Check Hellenistic philosophy. Maybe some more modern philosophies as well, if there are any that to descend back to earth and find a way to live happy life without having to explain foundations of the world and nature of knowledge nobody gives a fuck about.

Maybe some more modern philosophies as well, if there are any that bother to descend down on earth and find a way to live happy life without having to explain foundations of the world and nature of knowledge nobody gives a fuck about. Maybe also look into Cynicism for some ideas, but you'll never achieve that fully either. Generally speaking any philosophy that doesn't concern itself with what they call Eudaimonia is a worthless waste of time. And even those that do are still a waste of time most of the time. For example you never realize how much of a scam is Epicureans philosophy until you wake up in a war devastated shithole with no hope of future or anything.