Welcome, @Gustavo_Rip ! Sorry you’re having trouble.
Did you do a standard install? WIth a standard install, you need neither Nginx, nor Apache (and both use ports 80 and 443 by default). If you have either of those installed, you should remove them before starting.
Do you need multisite? Even if you do, I would recommend first doing a standard install, and then go about following this guide: Setup Multisite Configuration with Let’s Encrypt and no Reverse Proxy. I helped someone with it yesterday, and it looks like if you use the correct hostnames and don’t use Cloudflare with orange cloud it works just fine.