Old iPhone Restore backups on Mac

So I lost my notes on my iPhone, notes has an urgent yahoo password in that I desperately need! ( I understand my own stupid fault for storing it there!) I can’t get notes back via iPhone, notes are showing in outlook via desktop on Mac but I cannot find them they won’t show up anywhere and I cannot get any reply from outlook, yahoo are useless I am getting no help there!

next I’m trying to restore backup to the iPhone as this was an old iPhone the last backup was 2018, I plugged the iPhone in and it completed sync but I cannot restore backup as it states there isn’t enough free space on computer but there is!? I also cannot find the earlier backup from 2018 that I hope would still have the notes in it the only backup point I see is where it completed sync today.

Is anyone else able to help with this?

I was even willing to call yahoo to pay their subscription fee to get back in but I’ve been cutoff 8 times so haven’t been able to speak to anyone.

Maybe I’m just stupid but I can’t seem to get something that seems so simple on iPhone or Mac to work 😩