As I said above consider a Mobius C2 lens if you can make it fit . The HFOV is reported as 132 degrees for the Mobius lens, and should be more than enough for a decent view. I wouldn't describe it as optically perfect, but it's a good lens and in use in a lot of situations where wide angle is needed eg. It's widely deployed on RC Aircraft, as a Dashcam and in other uses. At $10.95 retail, the trade price for the lens is unlikely to be high, and it's coated glass not acryllic.
It's worth remembering a wider field of view isn't better if it's distorted. The aim of a doorbell cam isn't to see someone coming to the door, it's to record them and to that end it fails if they aren't easily recognisable.
I'd also say you have very little to lose by testing a Mobius C2 (beware there are other lenses - A, B, C (1) and D (some now discontinued))or other glass lower distortion lenses to see if you can improve the picture further.
However, nice product so far. Just would like to see a bit more image quality.