There are some known issues with LineageOS 16.0. Most notably, Wi-Fi-Display is missing and there are problems on older 2.4 GHz Wi-Fi protocols (slow download speed). If you can handle that, I recommend upgrading.
If you want to stay on 15.1, there are workarounds for the "missing apps" issue. Search this thread for "fingerprint".
I would like to try out the change of fingerprint to solve the issue on 15.1 itself. The post gives a link stating the procedure to do that using magisk. I haven't ever used it yet. But, remember to have read that it can be installed even without root and some modules do work without root too. I guess this one may not work though. Can anyone confirm, if you require root as well for it? Also, if installing magisk requires full data wipe (similar to factory reset)?