Problems with Windows 11 activation key

I had a fully activated Windows 11 Pro system using a MAK key. It showed as permanently activated and everything worked fine on version 23H2. After updating to the 24H2 preview build, Windows suddenly deactivated and no longer recognized the key. I rolled back to 23H2 using the Go back Option and the key worked again, Then I don't know why I did it but I saw another video showing how to use regedit to find the key which it showed me another key without the correct ending (that ends in 9BT6Y) and I also used chatgpt and it told me to use a certain command through CMD which I did with the wrong key apparently. and then it just inactivated my windows (after it was working) I didn't know it would do it I was trying to figure out a way to find the key so I can update it back to 24h2 version,

I used tools like ShowKeyPlus and ProduKey — they only showed blank or placeholders BBBB-BBBB-BBBB-BBBBI don't have the full MAK key anymore, and the system is no longer activated.

System protection/snapshots aren't helping, and I can’t find the key in my Microsoft account (it’s not a digital license). I'm considering buying a new key, but don’t want to get scammed by shady sellers.

TL;DR:

• Had an activated MAK key on 23H2
• Updated to 24H2 → Windows deactivated
• Rolled back → was activated again,
• No access to original key anymore
• Tools can’t retrieve the key
• Considering buying a legit key — but from where?