I own two gopros, and have seen knock offs that friends have bought... guess it's all personal preference, but the older versions of gopros are alot cheaper, I mean unless you need to shoot in 4-5k with the newer ones. The 3 and 4 are low priced and still do the job extremely well. I myself own a hero 5 black and a hero 7 black. The updates to the app have made them worthwhile tbh.
I'd recommend watching youtube comparisons with the top knockoffs vs gopros and see if any of those are good enough for what you want to use the action cam for. After that its better to ask yourself if you wanna risk buying an offbrand and not liking it and having to fork up the gopro money anyways... buy once cry once seems to be the biggest phrase in hunting/shooting/photography groups lol