1) quick find just doesn't work that way, see:
If you are only going to search one field, a simple scripted search would work better.
2) same issue
Ditto for "hide object when". The find operators are only supported in the standard find.
Here's a Hide Object When Expression that only looks at the last for characters of a field:
Right ( Yourtable::YourField ; 4 ) = "1234"
thank you very much for your answer. It's a little bit of a pity that both Filemaker features are more limited than I expected it, but fine. Have to find a workaround and at least I know now, that it's not because of my lack of expertise.