I need help!

Hi I am trying to downgrade the firmware samsung s6 edge + SM-G928W8 but it’s not allowed, I need to write cert using the tool but I can’t with new firmware. Is there a way to do this, Can I use twrp to do this, I need to flash old stock firmware and I already tried odin It gets stuck at cm. bin.. I don’t care if this trips knox or files are gone Help Any way to do this

Error I get

SW Rev Check Fail. Device: 3, Binary: 2