You're right. But taking Texgen over 1 hr instead of 5 mins couldn't be a Texgen problem. The logs where all good. I found the issue: the AMD GPU driver. I reverted back to version 22.5.2 and Texgen was fast again.
Maybe this helps someone else with the same problem.
Yea, yea, I know, I know. Thanks for your reply.
I just wanted you to know, because I didn't change anything in my load order. Just updated to 116 and reran texgen.