and saw the repo of hackliberty, they say to use alpine linux

On the same page you should have noticed links to excellent articles found on privsec.dev and madaidans-insecurities.github.io; both of which advocate other distros (as well) with the former not even mentioning Alpine. As for hackliberty’s usage of Alpine; I believe they stated it as their backend of choice for running their online services. So not necessarily recommended as their OS of choice on a desktop device. Though I’d love to be corrected if that’s not the case.

I was also looking to stuff like openBSD

If you can deal with it, go for it. Unfortunately I couldn’t give up my workflow to that degree. One has to be mindful, though, that however powerful openBSD is, one can elevate it further by using it in conjunction with Qubes OS; this guide might help you with that. Furthermore, this also makes it possible to not forego your entire workflow for the sake of openBSD.

just hardening the arch build I use rn

Also a decent choice, it might need constant tinkering and a lot of know-how to keep it splendid at all times. Though, it’s definitely doable as long as you’re committed and eager to improve yourself. And once again, this work doesn’t have to be for naught; once more this knowledge can be used to perhaps further harden an Arch-qube.

what do you think about that?

It’s always best to first define your threat model. After which it becomes clear to what degree you need further protection and what would be the best course of action to achieve that. For some, just moving from Windows/macOS to Linux is already a giant leap and might be enough for their threat model. While for others, this might not be enough as they have to be a lot more cautious to such a degree that even openBSD on a regular laptop might not be sufficient. If you just want maximum protection, then Qubes OS is surely your best bet IF you learn how to use it properly on a well-supported device; kudos if you can get your hands on one that support Heads as well. If you don’t mind a mobile device, then something with GrapheneOS should suffice as well.

IMO, you seem to be very new to all of this. Being overzealous might make you a lot more susceptible to burnout. Which is something you absolutely don’t want, as this is not a sprint but rather a marathon; keeping it up and going on is therefore of utmost importance and incremental change can help with that.