is the default policy block all?
if yes, you're fine. all that matters is that your network is firewalled off from the outside. Defense in depth should be practiced, but on a home network it isn't as important since you're not really a target.
I was just making a dumb joke about the data OP might be needing to protect lol, thanks for the advice though
Yeah this. If port forwarding isn't configured on the router, the router won't even know what machine to forward incoming connections to on your network. Furthermore, most Linux distros will not run publicly accessible services unless you install them and start them with systemd/init. Even still, many of these services require a tweak in configuration to accept connections from public IP addresses.
Do you have a hardware firewall? If so I wouldn't worry about it. Most consumer home 'routers' have such a feature. And in my experience that's going to stop anything you'll casually have thrown at you. The only issue with not having a software firewall is no control of outbound data but to some degree if you're running anything truly malicious and untrustworthy unless you're running it with limited permissions or virtualized you're already fucked.
