Hey @Manoj please have a look at this and see if it is worth promoting to an official how-to or a link to the official documentation:
[How-to] OnePlus 6 - Direct upgrade (dirty flash) of /e/ OS from Android 10 “Q” to Android 13 “T”
Please note the dirty flash part: differently from /e/ OS official documentation about OnePlus 6 upgrades, no actual flashing of stock ROM (hence wipe and reinstall) was necessary with the method I followed.