I would probably just buy used if you're going to dip your toe in that water. Unless of course there is a nice boxing 'week' sale.
100% buy used.
I've owned every GoPro from Hero 6 through Hero 12. My first 6 was bought new. I beat the heck out of that thing and when I sold it, it was still like new. Since then, all the rest were used. Upgrading hasn't actually cost me anything over the years since people are always impulsively buying or selling these things.
With GoPro, for $50/year I have unlimited video uploads and no questions asked free exchanges on any GoPro product I break (even if I intentionally break it). GoPro will just send me a new one like "lol, maybe hit it with a softer hammer next time!"
Now when it comes to Insta360... Never buy directly from Insta360. They're a really greasy company. They will not take back anything you bought from them once you open the box.
I bought an Insta360 One R Twin Set brand new a few years ago. I was immediately unimpressed with the quality and wanted to send it back. Three days after receiving it, they wouldn't take it back because I had opened the box. So if you really have to buy one new, buy it from a big box store or Amazon, do not buy it directly from Insta's website.
If GoPro's vibe is "We're happy to be a part of your adventure." Insta360's vibe is "**** you, pay me. Oh, you already paid me? Good, all that's left is '**** you' then."
A few months ago I sold my One R Twin set for $300 (far less than half of what I spent on it), and bought a used Insta360 X3 for $280. The used X3 was a minor step up. It's totally good enough for social media but I do 4K video on YouTube and on anything that wasn't sunny and clear the footage was just so-so.
I sold the used X3 for $300 within a month, and bought a used X4 for $400.
Now with the X4 it really does feel like I have come up a full step in quality from my original One R. I haven't played with it too much yet, but I'm cool with what I'm getting for the $400 I paid, but had I paid the $660+ after taxes, I think I would be disappointed.
The reality with these cameras is that what you see on youtube isn't what you get right out of the camera. A lot of those guys are either customizing all of their shooting settings like you would a DSLR camera, adjusting shutter speed, ISO, frame rate, exposure, etc. or they're shooting in log and then color grading everything afterwards.
TLDR: If you
really, reaaaallly need to buy new, just make sure you don't buy from Insta directly. I would get a used X3 for $300 if you just want some shots for social media, or a used X4 for $400 if you want to do some 4k footage stuff.