That's a nice theory but no.
There are several different kinds of configs.
The phone is global and not carrier locked, and you can make calls and sms and data.
It "works", just poorly. It works at a basic level, just not full coverage, not full speed, and not all features available.
Different countries use different radio bands, and so a phone that is nominally sold in a given country only enables those bands that are legal in that country.
So this phone is nominally for HK, which is the model with greatest overlap of supported bands with at least some US carriers. The hardware can do everything but the config that prevents it is sort of like a virtual hardware difference. In the past there might be different radio hardware, and now there is one hardware that is made to act like different hardware through firmware.
Without all available bands, you get less coverage and more contention with other users for available bandwidth. And your choice of carrier makes a big difference. Some of the mvnos only provide 2 or 3 bands total, while others might have a dozen.
Shizuku can not fix that particular problem. For that you have to be able to root the phone and edit some files in the rom. The term to search is "mbn hacking".
This has not been done for this phone yet, but apparently all the pieces are there to make it possible because the bootloader is unlockable and there is a way to unpack and repack a firmware.
I have unlocked my bootloader and tried to flash a modified bootloader to get magisk working, but it refused to flash the partition even though it's supposedly unlocked. So I don't have root and can't edit anything in the rom.
For another example, although basic 4g gsm works, there is no volte, vowifi, or vonr, simply because the carrier doesn't explicitly recognize or support the make & model.
But you can use Shizuku and Pixel IMS to enable all of those and they work fine. The settings in this case are tied to the sim. Once you set the settings they survive reboots and you can even uninstall the apps, but if you change your sim you lose the settings.