I have to get to use GPU, kdenlive chokes on two clips simultaneously, plays back with interruption.
Machine is way more than needed 24core/32GBRam/Radeon RX560 card.
The movit block is not selectable in settings although I checked I have Movit5 installed.

Is it maybe because I use an appimage ?

Movit on 19.04 AppImage is disabled as it runs not stable.

So is it stable if I compile from source ? or can Movit not work at all with kdenlive currently ?

I know it is not a system problem as Lightworks has no problem to run the same clips.

You can compile Kdenlive with movit from source but I'm not sure if you run into other issues due to movit enabled.