If i flash stock rom with odin, i lose twrp right?

I flashed twrp 2860 onto my jp softbank s6 edge sm925Z. 5.0.2 android.
I want to remove this bloatware trash.

Is there a way for me to backyp my current firmware
And then try another countrys firmware with odin, from the samsung
Firmware page?

Samsung does not release the jp softbank sm925z firmware.

So my question is, . . .
If i flash chinese firmware i will lose TWRP right?
Then i can not return to my backup stock rom. Because no twrp.

So i would need to hope i can reinstall twrp on the chinese rom right?

If i try other firmwares, i will lose wifi and cellular service right?

Is there a way for me to change or insert my wifi cellular partition information
To new roms or firmwares?