I have been using no-ip for around two years to remotely access my hosted service, I mostly use their free service except for a few 5 months offers I bought.
Recently, I received a full year offer in email for 8$ (COUPON CODE: MAY8), and I was wondering whether to get that or buy a 2 years domain for the same price (FROM hostinger or namecheap).
I have never bought a doamain before and my knowledge is limited to what I mostly read here. So, per your opinion, what would be better in term of usability and security, a DDNS on the router and a port open per hosted-service? or a domain with reverse proxy?
Another option is subpaths: xyz.ddns.net/portainer
Just one open port, to your reverse proxy (nginx or other).
The client updating no-ip with your dynamic IP is independent of the reverse proxy software.
While you can do that, you should be aware of the security implications (every application can see and modify every other application’s cookies). If at all possible, I would try to avoid this setup.