TL; DR: You can run any kodi package on your RPi3. The pkgdesc provide some frame of reference for users. I might tweak them to your point but honestly, once Matrix (19.x) gets released, we will simplify our Kodi packaging (specifics TBD).
Kodi on ARM is currently a bit complex. In order to be useful on ARM devices, you really need to have HW decoding to playback most popular formats (h264/x265). Historically, this innovation has been provided unofficially. There are currently three forks of Kodi we package. The two forks of Leia (18.9) are
newclock5 and
leia_pi4. The fork of Matrix (19.x) is
gbm.
Hardware limitations: Only RPi 4B/400 can use HW decoding for both h264 and x265 (HEVC) files. RPi3 series and RPi2 series can only use HW decoding for h264 files.
The first fork is
newclock5. It uses MMAL for h264 HW decoding. It can also playback some x265 content but it is not hardware accelerated and often choppy. Still, lower bitrate x265 videos could can be viewed on older series RPis particularly when overclocking. Next came the
leia_pi4 fork. It offers both h264 and x265 (including 10-bit) hardware decoding using the vc4-fkms-v3d driver. Note that the fkms driver is known to display some visual tearing artifacts and, in my experience, washed out colors (compared the kms-v3d). You can really only see the tearing in the Kodi GUI and the effect is minor, honestly. Finally, we have the
gbm fork. This uses the more mature vc4-kms-v3d driver to offer both h264 and x265 (including 10-bit) hardware decoding without tearing. As I noted comparing fkms (in leia_pi4) to kms here, the colors appear deeper and more vibrant, at least on the hardware I have.
Both
newclock5 and
leia_pi4 will never mature past Leia (18.9) as stated by RPi and Kodi developer, popcornmix (cannot find reference). The patches against ffmpeg contained in
gbm have been submitted upstream. it is expected that they will eventually accepted and that Matrix (19.x) can ship with them natively.