Hi Sebastian, sorry to hear that your website performance is down after installing Total Upkeep and we will do everything we can to help you get things working as expected!
Total Upkeep shouldn’t be running any processes on the front end of your website that would affect performance and we would appreciate your help in figuring out where the issue is coming from. Could you send us a link to the GTMetrix report that had your website loading at 23 seconds?
I ran a report of my own on your domain and got a load time of 5.5 secs, is Total Upkeep currently deactivated on your website?