Yes, I highly recommend the Heidenberg!
The forest is ugly commercial forest in SOME PLACES, where the erosion caused by MTB is not important.
In the "carousel" in the eastern forest, depending on your previous knowledge, you can start with simple exercises that can be increased to the point of a death-defying jump over jumps.
In the western forest near the transmitter mast to the south there are three great downhill routes that are great fun and are also suitable for beginners because the jumps are clearly visible (!) and can be avoided.
If you don't want to go back up the marked, gravel hiking trails via the downhill tracks, you need a strong will and a lot of strength, coupled with a certain amount of stamina, because the bikes often have to be CARRIED.
In short: If it says downhill, you should avoid uphill. Start at the top to see for yourself.
A good starting point (middle between east and west, large parking lot) is Kühedorf.
On the way back you can visit the very enthusiastically run Gasthaus Kraft at the parking lot. It looks typical and inconspicuous from the street side, but is surprisingly good in every respect - they even serve hot meals all day long in the middle of the week.