Can I backup on oxygen OS and restore to lineage OS using adb backup? I have a OnePlus 2 that is running stock Oxygen OS. However, lately, I'm not happy with the phones performance. Therefore, I would like to try lineage. I would like to keep all my data (apps, chat history, photos, contacts, etc.). If I use adb backup, can I restore this backup after installing lineage to achieve the desired effect?
It's possible, but be specially cautious when proceeding.

An ADB backup contains system settings, which is likely to be different across ROMs. Blindly restoring an ADB backup from another ROM may render your device unbootable.

If you restore only the apps and their data, you'll probably succeed.