Extended timeshift uses an older http server in NextPVR that doesn't seem to work that well with Kodi and I never really figured out why that extra buffer time was needed but glad you got something working. The technology is changing for v5 of NextPVR so there is little point in developing this much further. Perhaps the dev. who wrote v18 timeshift will one day fix the problem that lead me to work on the alternative.

Kodi and NextPVR don't need VLC so that is not the source of the problem. There is a hook to VLC in the older NEWA "classic" web interface but I don't think many people use that anymore.