Welcome! There is so much content in ukso so you have come to the right place. It depends what your trying to achieve when you say "better" faster, cleaner, newer, ice, restoration..
It looks great! Your carpet install is Bang Tidy! Were did you get it looks like a great colour match for the OEM one and you got it fitting so snug what adhesive did you use?
Been going through old SD cards and this is what I found.. didn't take many pictures though the actual build process unfortunately but was allot of fun building it.. 😁
Well you mentioned you just changed belts and alternator so I assume the problems lays there, if it was running fine befor. Alternator belt and power steering belts are easy to loosen I'd start there.
If one of you auxiliary belts is to tight it can make that noise. Happened when to me with my power steering pulley belt when i junked my AC. Try slakening a little might just be to tight