Trying again to find out why my preview stutters after 30 minutes

Please help me kind people. Here is my log file as requested. I use a PAL camcorder (as in UK) and I am getting stuttering (to half frame-rate) in full-screen preview after 30 mins. If I am playing a media source behind the video capture, the media source is also affected. I have spent so many hours trying to fix this. I am not interested in gaming or streaming and am happy with the preview and filter effects. Maybe there are better alternatives? The analyser says the framerate could be a problem, but can we not use OBS with cameras in the UK? I can change the camera to NTSC 60fps, but it's a little complicated and there might be an issue with indoor lighting, but willing to give it a go if you think it's worth trying. Thank you! https://obsproject.com/logs/XrQ9J1IHkeqaTBpn

The analyser says the framerate could be a problem, but I managed to change the camera framerate to NTSC 60fps and it still fell back to 30 fps after 5 minutes. Wont anyone help me?? Been seeking support for weeks now.