How can my compost rot faster?

Hi,
we seem to be doing something wrong with the compost. Three years ago, we had a lot of grass and piled it all up in one heap. Now we wanted to spread this as soil, but it is a slimy, tar-like mass with grass still in it. We also used this [Schnell Komposter], but that stuff seems to me to be pure fraud.
Is there any trick to make the greenery rot faster?

Pouring chemistry on top

A pile of grass is not compost ... Air (oxygen) was missing inside the pile. You can add grass clippings to the compost, but alone it won't work. Compost should be placed directly on the ground, it should be mixed with regard to the materials, and it should not cool down too quickly or dry out.

Perfectionists turn a pile after a few weeks (this ventilates the already decomposed layers at the bottom).

If you have a lot of grass clippings, you can use them to mulch under shrubs and hedges and on beds, i.e., spread the fresh (!) clippings in a relatively thin layer (no more than 5-10 cm) on the soil.

Yes, the grass clippings are now immediately mulched by our mower and no longer go on the compost. So, lack of air problem. We have now spread this "sludge" out - this way it gets plenty of air. Maybe that will solve the problem. :)

Mix with soil rich in organisms. Steal good soil with plenty of worms, woodlice, springtails, beetles, mites, etc. from yourself or the forest edge.

Then air. Then time.

Once the thing is running, add layers about once a year.

Layers?