Yesterday I was able to install (3) different customROM’s on the Galaxy S9+ ‘star2lte’ with TWRP 3.5.0_9-0: first /e/OS ‘Q’ e-0.13-q-20210120, then LineageOS 17.1 for microG and finally /e/ OS ‘Q’ GSI ROM. The starting point was Stock Android 10 Build December 2020.