Looks like the price is tied to I/O palette and spending hundreds more on something i will never use seems like a bad idea
Absolutely correct.
i think its a waste to have such mobo if im not even going to OC or use PBO
Outside of Alpha (as top contender for OC) and Taichi (as slightly weaker than rest), almost all of them have equal capacity for overclock. Some might do better in cases with stronger airflow (Gigabyte), some don't need almost any (MSI), but ultimately the difference seems very small like in the recent Hardware Unboxed video someone posted few pages back about Alpha.
There is bit of feature gating (ethernet..) and intentionally making the "entry" level boards look worse/game-rish but after you close the case you won't care at all.
Aorus Master looks like a nice middle ground but i read that some people are not satisfied with them
What exactly? Only one I seemed to come across was the bios issue related to AVX instruction set that was actually due to AMD and it was fixed last week. One guy made a thread where he almost alluded to this being hardware VRM fault, and it turned out to be trivial thing. I myself downloaded the latest F4d bios for my Aorus Xtreme, run the Prime95 from that scenario and everything works correct.
Outside of that.. I haven't seen almost any mentioning of Gigabyte TRX40 Boards (or MSI/Asrock for that matter). Asus brand is still so strong, that they out-sell others 10:1. But since this is my first Gigabyte board, and I have lot of Zeniths (for X399 and X299 alike), here is one my opinion. I really like the UEFI so much more than Asus's one (and found the MSI one terrible). It's easier to use, there are no artificial limits (like 85C temp for custom fan curve,etc..). And from X399 generation, I can say that both Asus and MSI stopped bios support very early. I feel like Gigabyte tries the hardest to get foothold by having really bios support.
That said... you might as well spin coin or get what you're able to actually buy for good price and availability. You can't go wrong with anything.