I really find a lot of what is spoken vague and hard to distinguish the actual sounds... many spill over into what could be another consonant or vowel sound.

"Schüssel" only has one L.

That is because Schlüssel is key ans Schüssel is bowl. See how one has an l after the sch and the other doesnt

It's the difference between bow and blow

I am often confused here too

fell for that too

Schlussel and Schussel are different things

Coincidence

"Du bist eine Schüssel", if I were to guess. It's just context.

Edit: After checking a few dictionaries, I don't think scatter-brain is actually a definition of the word Schüssel.

Re-edit: The word you're looking for is der Schussel ;)

Schlüssel is cognate with slot. That's how I remember.