Windows is forcing me to give them another $280 for a new license!!!

Back in 2020 I bought and built my first computer, after building I bought windows 10 for that computer. One day when I got on that pc I noticed that I could upgrade to windows 11 for free. Great and everything was fine. I began gaming and started to stream online. With that I got another computer from a co-worker and loaded windows onto that pc. When I got that pc up and running I had a message that windows was not activated on this device but I was able to tranfer windows from a store bought laptop through my Mircosoft account. To keep everything on track the computer that I bought back in 2020 will be referred to as PC1 and the one I bought from a co-worker will be PC 2. Now fast forward to today. I was needed of a upgrade on pc2 due to stream quility issue so I had a great ideal to upgrade pc1 for better gaming and replace pc2 parts with pc 1 part. That is what I did, I took all parts from pc1 except the GPU and put them into pc2. Pc1 got new everything excpet for its GPU. I also erased both hard drive because of the type of change I was doing. Everything went fine except now both computer are saying that I dont have a activated version of Windows. I have just spent 1hr with a support person and they are telling me that becaused I upgraded my hardware I now have to repurchase Windows for both computers. What happened to my other versions I do not know. I asked if there was a discout and no there is not. I dont understand how just simply upgraded my pc caused so much issue. The support persons said it was due to a motherboard change but that dont make since due to pc2 still haveing pc1's mother borad. Maybe I'm stupid and dont know a crap ton about pc's. I just dont think that because I upgrtaded my pc I should now have to again buy windows.