How to use setprop via adb shell in recovery?

I messed up flashing a beta Android Q build on my phone. After that, I can't flash my stable ROM without error 7 in TWRP - device mismatch. Removing the assert works, but not a permanent solution. So, I digged through google and my own phone for hours and found out why. My device is identified as raphael in recovery, but it is identified as raphaelin in fastboot and while the phone is booted. In recovery:

# getprop ro.product.device
# raphael

In booted mode (i.e. while the phone is booted):

# getprop ro.product.device
# raphaelin

In fastboot:

> fastboot getvar product
product: raphaelin

I checked my build.prop and the value in that file is raphaelin too. I tried setprop and it showed that it can't set that property. So, please advise me on how to set the value using setprop in recovery mode. Or, if you know, please let me know from where the recovery is pulling data for getprop and if I can change that file.