Switching schools, no clue how to make friends

(Sorry if I’m saying anything wrong gramatically, I’m in Germany + know 4 languages, which is why I often mix up everything)
I (F) am switching schools after summer break, but that is because I couldn’t talk to people in my current school and I was seen as the unfunny girl during/after covid. Before that i was a huge extrovert and did everything I want. 2 Years ago and i would’ve never experienced any fear in doing anything, I could go up to strangers and hold conversations with them. Overall rn I’m trying to be nice to everyone, so I can’t say no or decline anything so I don’t destroy my image and leave a nice version of me in everyone’s memory becore I leave. If someone asks for notes, homework, test answers ect. I just give it to them. I even did someone else’s homework stayed awake until 4. I had 1 hour of sleep. If I say no, I feel guilty. I’m trying to be helpful, nice .. so people change their mindset about me, cause that’s what I ruined, but nothing seems to work. When I told everyone I’m switching, no one reacted, they didn’t care. I might be overreacting, but when one of my classmates came over to my trio-ish and said she MIGHT switch, they were almost crying and saying stuff like “awhh you can’t leave, It’s only two years come on” I still don’t know what I did wrong, and even though I stopped talking to everyone, whenever I ask why they never talk to ME, they answer “you’re annoying” but have no exact reason.

I realised all of this when:
1. Around 22nd February my class went ice skating, after that everyone tried avoiding me and my ex bsf (M). We went to my ex-friendgroup. They told us they were just buying a book and going home already.
When we were gone, we saw them at some burger house on their snap map, but we didn’t care. An hour later I got the feeling they’re following us, so I said hi. They ignored us and said They’re going to a store which was the store I was planning to go to. When we were in there, someone from the group asked me to pick an outfit for my exbsf, and said they’re doing the same for eachother. When I walked away I watched them for a bit and saw them waiting until I leave. Me and my ex bsf met the friend group at H&M again, and when we were in there they told us the same thing again. This time when we were together, I turned around and saw ALL OF THEM (excluding my exbsf) running away from me into a random store. When my exbsf ran after them, which I didn’t wanna do, they told us to go away. I decided not to speak to anyone for the rest of the day and started crying the second I arrived home cz I was super attached to the group, and I’m super sensitive

1.1 The next week when my exbsf was sick I walk home from PE class with a friend I used to be close with. Lets call her Aubrie. I did her homework, sent her everything from skl, yet she stole money from me and believed her ‘cool friends’ over me in return. (situation is explained in 2.) Aubrie was in the group as well. We went home from PE and when the group split I see the 2 leaders (Let’s call per1 Nick, and per2 Moe) of the friendgroup looking back at me, and then Nick is *whispering* loudly “I don’t want her in our group, but it doesn’t feel that good if we exclude her. I don’t like her” He’s very popular in class so if he dislikes 1 PERSON, no one likes that person. When I heard that , I felt that chest pain thing, not because I had a crush on this guy, because he was one of the people I liked the most in class. Moe agreed, even if we were good back then. I cried the whole way until I got home.
THAT was the day where I searched schools near me, explained to my parents that I ‘want to switch schools because my teachers can’t teach’ which was obv a lie, but only so the friend group doesnt get in any trouble. A month ago I decided to tell my dad, friend? and teachers the truth. It felt so good knowing I can speak freely about something.

1.2 the next day we had music lessons, i sat down next to Aubrey to see if she was on their side. I told her “I felt like Nick didnt like me” and she was panicking, answered “He gossips about you with the group so often, the friendgroup dislikes exbsf too” super fast, but why would she even know.

1. 3. While this happened, me + Aubrey were best friends. There’s this other popular friendgroup Aubrey was in. She forced herself inside, everyone could tell. It was a class trip with my old teacher, and we went hiking. I see her dorm partners walking in front of me, saying “she doesn’t deserve to be allowed staying at the dorms, but I’m happy for (boy1) for being allowed” then they talked so much about her PE outfit, roasted her from head to toe. When we arrived at the dorms, (it was 5 hours so there was much more going on in that convo), I rush to Aubrey, skip dinner, just to tell her everything I heard. (Fyi they’ve been doing this for YEARS) She asks me “Are you fr?” Next thing I know, I return to my dorm (sharing with 3 girls) I hear banging on the door. It was Aubreys ‘friends’. Aubrey told them everything I told her and believed THEM, over her bsf.

3.Back to the group, my 2 current friends? were still in the group, and they always gave eachother invites to parties IN FRONT OF ME and I was invited to ONE out of 17 by my exbsf (M).
They talked about the larties before they started, and after it ended, and in front of me

(Not necessary to read: My exbsf might seem super nice but now hes js super cocky now and texts me stuff like “Me, (p1) and her brother were at (festival) until midnight. Now we’re driving home together” randomly, even if I’m not talking to him. I’m not even jealous atp it’s making me giggle because it’s just embarrassing)

This happened bc of my past behavior (3-2 yes ago) when people saw me as weird and stopped talking to me. I didn’t want to change on purpose, it just happened so suddenly and I became an introverted girl who couldn’t hold conversations with anyone, not even with my 2 friends, who clearly didn’t know how to talk to me.

I had 2 test days at my next school and the people were so nice, but I’m still worried. I have no clue on how to make the first move: “Wanna be friends?” “Let’s work on this project together” (starting a conversation).. bc I’m also worried about saying smth that doesn’t fit in. I generally think it’s awkward.

If I couldn’t make friends in my old school, how am I supposed to make any in my new one? I have many online friends but I realised everyone had to make the first move, even in texting: they have to send something first so I reply to it
Any advice would be helpful 🙂