Switching carrier firmware Can you flash different carrier firmware on the exact same model phone

For example can I take a Straight Talk Galaxy S5 and Flash u.s. Cellular Galaxy S5 firmware to it and make it work

Reason why dropped my s 5 for u.s. cellular and broke screen I was at Walmart today and seen a brand new S5 for straight talk or some other Walmart carrier and it looks nice I thought it'd be nice to have my S5 back and have a brand new one at the same time
Different models use different baseband hardware and software tuned for the carrier's operation bands.

From what I found through search, a Straight Talk S5 (SM-S902L) is a Verizon S5 (SM-G900V) minus the bootloader lock, which supports LTE band 4/13. This is distinctly different from a US Cellular S5 (SM-G900R4) with LTE band 2/4/5/12/25.

Unless you've seen explicit examples that cross-flashing a baseband worked, don't even think about it.