LineageOS 14.1 (Android 7.1) remains the most functional custom ROM, though it is now quite old.
Use TWRP to make a "Nandroid" backup of your current system. yt3850f custom rom updated
Lenovo Yoga Tab 3 8" (YT3-850F) , finding updated custom ROMs is challenging because the device's hardware (Qualcomm Snapdragon 210) has limited community support compared to the "Plus" version (YT-X703F). Customrombay.org Available Custom ROM Options LineageOS 14