First unlock your bootloader if you haven't already done it, there are many tutorials on the internet.
Download Blu_Sparks OP6 TWRP 9.86(.img and .zip) or newer.
Then boot into bootloader and do: fastboot boot twrp-3.2.3-x_blu_spark_v9.86_op6.img
When you're in TWRP go to Advanced>Adb sideload and start it.
Then do: adb sideload twrp-3.2.3-x_blu_spark_v9.86_op6.zip
After that installs, reboot recovery. Then go to advanced>adb sideload and start it again
Then do: adb sideload Magisk-v17.3.zip
after that finished just reboot back to oos and you're rooted!
Blu Spark twrp: https://forum.xda-developers.com/dev...7466#downloads
I'm the first rooted earopean OP6T consumer ever.
If you need any help ask me on my telegram group: https://t.me/xOP6T