I am trying to get F-Droid working with the Privileged Extension on my Google Pixel running Lineage OS 16. Honestly, I am not really sure I am even installing the right things. I have read this thread over and over again and I think I understand most of it but the exact install process is still not really clear to me. Also, I wonder if the fact that Pixels have the whole A/B partition thing might also be complicating things for me.
(This is the part I am not so sure of since lots of what I read about installing the PE says to use TWRP. However, my understanding is that due to the A/B setup on the Pixel I need to use the LOS Recovery to sideload things).
Might be worth mentioning that at the same time I am also sideloading MindTheGapps and the los suaddon and those seems to work fine.
Thank you all so much for your help! To be clear, I had checked the Expert Mode settings and there was no checkbox for the Privileged Extension. Also I had verified that the privileged extension app in F-Droid was not marked as installed. (Should have included that in my original post).
However, I did go the Magisk route and it worked! (Had heard in passing about Magisk, but had not really looked into it before. It is awesome!)
Just to be clear in case anyone else runs into this same issue with the same setup: To install Magisk, I downloaded the zip linked from here onto a host computer and then booted my Pixel into the LOS Recovery and used the adb sideload feature to install the zip. Then I rebooted the phone into LOS and downloaded/installed the Magisk Manager app (also linked from the XDA page above). In the Magisk Manager app, I went to Downloads and searched for “F-Droid Privileged Extension” and installed that module. After rebooting the phone again, I downloaded and installed F-Droid from https://f-droid.org/FDroid.apk. Then, when I opened the app and went to the Expert settings, I could see the Privileged Extension box and it was checked! I tested it and was able to install an app though F-Droid without the extra installation dialogue.