Global vs China

I just discovered on Xiaomi 13 there are MANY 4G bands missing.

My house have only B20 coverage, not present in Xiaomi 13.
Near cities have B3/B20, or B3/B7/B28.
No B7 and B28 in Xiaomi 13 neither (why???), so my speed will go down (no 4G+).
Why Xiaomi did such horrible thing?
People travel all around the world with a phone, why limit connections in that way? There is no logic!!

For the second time I regretted buying a Xiaomi phone.
I had Apple, then Samsung, NEVER got problems with firmware or language or frequency.
It is my first time with Xiaomi, and probably last time too.

So sad, watching main phone features looked like a very good phone.
Unfortunately there are many hidden bad things.
I completely agree. I think it is an artifact of the phone basically being designed for china 1st, then it seems like the global part is an afterthought. I don't really know. The information is clearly published so I wouldn't say it is hidden. Especially someone like me in the US has to go out of their way to import a phone. Even if it supported all the US bands, it still might not work because the US carriers have started whitelisting what they allow on their network based on "certification" (which phones they make money on)

This is the main reason that stopped me from buying at 13U.

With the 14 and 14pro out and the 14U coming out soon, I hope that the bad coverage is improved.
I've been waiting on that before I settle on a final decision.

Though I've also read that the 14 series has made it more difficult to unlock. If I can't change the ROM, that may be another issue stopping me from buying.
Indeed, but what I'm trying to say is network band support is part of the SoC, it's unlikely the SoC is different for different markets as it will be very costly to produce like so. Therefore, the SoC as a hardware actually supports all bands, but the decision to enable or disable is determined by the firmware written by the smartphone manufacturer.
Also providers can limit the scanned bands for faster search in certain areas....
I also look for something to enable scan the whole range phoone supports. I need N77 for privtae use.