Leute, ich bin so müde, mein Aglaonema verliert ständig Blätter (sie sind alle krank), was mache ich falsch? Ich möchte es wegwerfen …

Looks like thrips damage. There are tons of posts if you search about thrips treatment. What you can buy depends on what country you live in.

Insecticidal soap, you can buy or make by diluting a weak detergent like dish soap and adding a few drops of essential oil. Depending on your available soaps, store-bought may be more effective.

Soap works by removing a protective film from the bugs, so they dehydrate and die. The trick is to repeat twice weekly for a few weeks, even after you think bugs are gone. The reason is that eggs aren’t affected, so you’ll need to get any hatchlings, ideally before they lay new eggs.