Hi, look at this post back from a discussion in July 2023. Here I have provided my documentation about setting up the satnogs-auto-scheduler. 
Maybe this helps. 
You can check if your auto-scheduler works by appending the -n option, which computes the passes but does not schedule them, by simply running your command within the satnogs-auto-scheduler directory (In your case this the directory where you have installed the package by running the virtualenv, pip install, commands …). E.g. as provided within the README file you can run following command:
schedule_single_station.py -s <ground station ID> -n
where you need to replace <ground station ID> with your ground station ID, e.g. 3045.
Note that you have to change beforehand into the the respective directory, e.g. by running following command:
cd /home/pi/satnogs-auto-scheduler/env/bin/
As I can see from your posts from above the correct path for you is:
cd /home/pu4elt/env/bin/
since you did not setup a new folder prior to installation.
To know if your crontab work, I would suggest to set your crontab timestamp to something in the future and simply look if your satnogs-auto-scheduler schedules the desired satellite passes. There are crontab time generator available, just google them. Moreover, there are some other general ways to test if a cron-job works. Just google for “How to verify if crontab is working”.