Multiple keychains and not working correctly

Hi, I have a Macbook Air 2024 M3 with 8gb RAM and 512gb memory. My memory is getting full and I have been trying to make more space. Stupidly I asked an AI how to do this and was told to go to library and delete all the cache files. I did this and created so many problems that I had to re-install the OS. Since them my Keychain hasn't worked properly. I have tried to fix it and seem to have created even more key chains (7 I think) and it seems that some passwords are stored in different key chains. Every time I restart the laptop I have to enter password after password to get everything online and working. Does anybody know how I can fix this? Get back to one keychain, and move passwords stored in the other keychains all back into the original one?