As a suggestion @brunmargofc I suggest you read this thread and all its links…
http://forum.bubble.io/t/solved-new-more-eyes-on-website-improve-seo-with-cloudflare-subfolder-instead-of-subdomain/180078
One answer is to put a web proxy (think Nginx as a reverse proxy on AWS or something like this) and proxy by path eg
https://client1.com/bubbleapp proxies to https://tenanted-app-in-bubble/?tenant=client1
https://client1.com/not-bubble proxies to https://not-bubble
https://client1.com/blog-site proxies to https://www.myghostblog.com/client1
etc etc
Then to search engines everything looks like it is served from the domain https://client1.com
However this requires
- AWS costs (or whatever you use as it will consume bandwidth)
- and obviously Expertise to set it up and maintain it
But it’s a thread to pull on 