I am trying to process a timelapse that I shot with my Canon r5c, but as soon as I try to create visual previews it keeps overwriting "Visual Lum" and it gets stuck in an endless loop. Its also strange that I get an error that my timestamp is in the future when I load the images, but they are clearly not.

Same software, same procedure with stills from my Fuji GFX-100II or Hasselblad X2c, everything works fine and as expected.

Can it be that LRtimelapse is not compatible with Canon R5c?

Do you have the latest Adobe DNG Converter installed and the latest version of LRTimelapse?
Please double check. DNG Converter link on https://lrtimelapse.com/install/
Also check that the Capture time is really not in the future. If LRT reports so, there should be a reason for that. What does the column Date/Time show in the table?

If the problem persists, send me the log file after this happens. And it would be good, if you could also send one of the raw file via wetransfer or dropbox to support(at)lrtimelapse.com