I am interested in exact same use case (Eufy & Ubuntu Security Camera DVR). I cannot contribute much, but assume you have seen DIY security camera community's standard? Blue Iris is very popular software (not free, but not expensive
, with many useful features & online help for most brands & standard situations. Just not really for me, so hope your thead generates some looks & feedback!
EDIT: good point by
@mmo, I forgot to include Zoneminder. Very popular with DIY community, and free
.