UFW, by default, blocks all incoming requests. This means that SSH (port 22) is blocked already. Then, if you need to, whitelist (ALLOW) ports that you want to expose to the network. For example, I have ports 1714-1764 whitelisted for KDE Connect and everything else is blocked.

It doesn’t scale properly on my HiDPI laptop display, which I use at 200% scale (Plasma 6, Wayland). Some things are too big and others too small. Hopefully GIMP 3 will bring good scaling support with GTK 3. Still, I love GIMP and will continue to use it over any alternatives.