I recently picked up a HDHomeRun Flex 4K and the Zuki add-on is working perfectly for me. It does require a subscription to HDHomeRuns DVR service at $35 yr USD though. It is not official but it listed on their forum so not quite unapproved either.
I rather like that with a hard drive plugged into the box and the subscription the entire thing runs standalone without any PC or client device needing to be on for the DVR to do its thing. All timers and recording in Kodi are reflected in the official HDHomeRun app on iOS/Android/Win10/etc and vice versa.
Before I paid for the DVR service I did try out the HDHomeRun client that is installed (but disabled) in the beta OSMC Kodi v19 release. It seemed to work just fine but is lacking the ability to record and only has a days worth of guide data.
The Zuki add-on has to be installed via zip you grab from their github. The armhf version works for both the RPi’s and Vero 4K’s and can be found here…