It is totally fine to be politically moderate. I’d go as far as to go full mathematics professor and claim without proof™ that centrists being tolerant of intolerance and extremism is a thing mostly made up by extremists to discredit them.
I can only speak for Europe, but pretty much every center party you will find here actively opposes such things. They don’t go around and beat up nazis on the streets, yes, but that’s not the kind of opposition I’d expect from a political party to begin with. If you wanna do that, that’s fine by me. The thing is, I have a strong feeling that particularly far-left splinter groups tend to conclude that “centrists bad” or even “centrists basically nazis” because they don’t agree with them or their methods.
That said, if you ever want to have any say, your only choices are compromise and violence. It is a huge problem that broad alliances are very hard to achieve among far-left, moderate-left and center parties. At least for people who wish to have a left or left-leaning government. Why do we hardly ever get one? Well, I’d say usually the moderate parties are there, ready to pick up the crown, while the left is fighting over which one to safe first and the most once they claim it. And all that is preventing the far-right from claiming power (if anything at all these days) are the center parties some people want to hate so desperately
I would sort myself into the social-liberal drawer. Moderate left. I think reasoning with nazis, tankies, religious fanatics etc. is a waste of time. I also think you’re best off creating an environment where as few people as possible become either. And I think the main ways to achieve this are welfare, education and psychological support. The thing is, I want to make this happen at almost any cost and not just demand it for the next 50 years.
Zen and “mainline” (default/vanilla) are generally fine for “desktop use” and gaming. Zen is basically the mainline kernel with some tweaks. They are mostly concerned with latency, reducing the maximum time a process can spend blocking the processor - among other things.
This can lead to less input lag or a “smoother” desktop experience, but overall performance is as good as mainline at most. Slightly worse in some scenarios.
Hardned is a tradeoff afaik. You will stay behind mainline a bit, but get extra hardening. This can also impact performance, but rarely does in a meaningful way. If you don’t have any specific reason to use it, e.g. you carry it around on a laptop with sensitive data, I would look at other ways to harden my system first (firewall, encryption, access control, anti-virus, sandboxing, VPN…).
Pretty much the same goes for LTS, but with the focus more on stability than security.
RT is only for special applications.