Siteler aynı hedef siteye bağlanmıyorsa, aynı barındırma sağlayıcısını kullanabilir miyim?
Diyelim ki A sitesine bağlanan 5 sitem var. Her site farklı bir ana bilgisayarda.
Diyelim ki B sitesine bağlanan 5 ek sitem var. Her site farklı bir ana bilgisayarda, ancak bunlar ilk grupla aynı.
A sitesine bağlantı vermiyorlar.
Bu hala bir ayak izi mi yoksa insanlar bunu bu şekilde mi yapıyor?

Yes. I have been doing it that way for 15+ years.
Dude make it a little less complex with your explanation. You should have asked if 2 domains can be on the same IP (it doesn’t have anything to do with hosting providers). The answer is NO, it can leave a footprint.
And also you can host multiple sites with the same host, but you have to take notice that each site should have a unique IP.
Of course, as long as they don’t share IPs that’s okay.
Easiest is Digital Ocean/Vultr, for this. One droplet = one dedicated IP = one PBN.
You can put many sites on same server in any configuration needed , be sure to put Cloduflare in front so direct IP can never be known .