SSL problems using Cloudflare

Thank you for your reply. I tried again form zero, all DNS in Cloudflare are “DNS only” (grey), removed all certs (CP and Clouflare) in /etc/ folders and reissued SSL. But still doesn’t work (for example “ERR_CERT_AUTHORITY_INVALID” error or SSL not found in some online SSL checkers).
I don’t want to show you all the steps. But the I realized that I forget to tell one (important) thing : I changed the port to 8443 (bypass cloudflare firewall). And read that port 8090 is hard coded. Maybe that’s the reason ?
Maybe I can start again from zero with the 2 following links, of course keeping your advice concerning Cloudflare proxy) ?

or (the rewrite rulkes are a little bit different)

Again, many thanks from a former CPanel and managed VPS user.