Alright I've been playing around with MPC-HC 1.7.9, AviSynth+ and SVP 4.0.0.60.
It has been surprisingly very stable but I just got a freeze after playing videos about 20 videos without issue. The freezes only happen when loading videos.
Then I'm loading AVS scripts instead of opening the video file directly; I'm not sure if it would still crash if I open the video files directly.
EDIT: I've got another crash when loading a video directly. Still totally random, but it always happens when loading.