As a dev: for all their flaws, web apps are easier to distribute, portable, and have a lot of support in frameworks. They also require little infrastructure in most cases.
As a user: web apps run without installing anything, are mostly portable between my browsers of choice, and run in a sandbox to protect my computer.
Probably 90% of my needs can be served by a web app if it is well designed. If I can’t have a web app, I will look for a flatpak version and failing that I will look for it in my distro.
In my humble opinion, being monocultural as a developer is a path to obsolescence. Be T-shaped: know your specialty really well, but also a bunch of stuff more superficially.
If you have a little hands on experience with Go on top of your Java expertise, you are imo more valuable to your employer. They may even be mid transition from Java to Go, where you would be very useful indeed.
Besides, it’s just healthy to keep learning new things.