Would this count as a PBN?

I bought a few domains that are in my niche and will be doing 2 things: 1. Pointing the domain name back to my main site 2. Rebuilding the website from archive and adding a few links back to my original site. Would this send a bad signal to Google? The sites themselves are aged and not AI. They are relevant on the topic and helpful on their own, I just want to spice them up a bit to build a better backlink profile to my site and capture potential visitors who may visit the rebuilt sites as well.