Since this morning my F3 LOS got stuck during boot. The typical boot of LOS keeps running. I have LOS installed on my FP3 since April th 2nd and is up to date, thus including the update from April the 14th.
Then what have I done yesterday, you may ask? Downloading some videos and updating some apps with both F-droid and Aurora-droid.
In case my FP3 LOS get stuck, because my internal storage is full: How do I delete some data? My files are already synced with SyncThing, thus those files can be deleted. It is suggested here: Booting gets stuck - maybe full storage
In case my FP3 LOS get stuck, because some updates got wrong: How do I uninstall those apps? They are from some known shops here in my country, and such.
In case my FP3 LOS get stuck of some other reasons, feel free to guess
EDIT: With some patience, LineageOS told me that I had two options: 1) A retry, or 2) a reset. After another try with the same two options, I decided to do a reset, because I had have the time to do so. That went well without any problem. Thus I am now reinstalling everything and then doing a backup, so that I can use that backup when this will happen in the future.