I’m paying 25€ for 600/300

One solution would be sending email requesting for them to open ports for you, you can tell them that you need open ports for security cameras and use that port for reverse proxy. That way you dont need more than one open port. Second option is cloudflare tunnels, they do not require open ports at all, but they do require for you to buy domain though. Last option would be to use VPN like tailscale which also do not require open ports at all. All you need is clients installed on devices and connect them on the same network.

Hope some of these help, i actually use all methods for different situations and each of them have pros and cons, but those are all reliable methods.

Oh my server is running through cloudflare tunnel so im not affected by ip change at all. Im actually running default ISPs router it’s actually pretty nice and does the job for me.

God, i love how nice everyone is on lemmy right now.

I think it depends on the ISP. In my country (Croatia) most of the ISPs, if not all, change your IP address every 24h no matter what. You can force the IP change when you restart the router so if I restart mine at 2am it will change my IP every day at 2am.