Nag-check ako sa mga forum, I found something. You're device was in Prenormal State (Pre-installation mode), additional security ng samsung before and it may take few days para mawala yon—automatically. Pabasa ng mga pag-uusap dito sa LINK na 'to. Nandyan yong topic, at tong mga possible way to...
Yong twrp ay .tar or .lz4 ba? Di mo kasi yon mapa-flash via odin if di ganoon.
If ever na kahit ganoon, ay di pa rin kaya. Unlock naman bootloader mo, no?
May screenshot ka ng error at ng .img na sinusubukan mong i-flash?
Also, may chance na wrong variant ang sinusubukan mong i-flash kaya nade-detect as different or non-official firmware.
Try to read this, lods. Baka sakaling makatulong: Realme 8
Also, look at his other post, about unlocking bootloader. Theres a post in that sectioj about custom rom, LineageOS 19.1, in case you want.