WEN JN8504 8.5-Amp Plate and Biscuit Joiner with Case and Biscuits

I’m confused ! every video i watch shows pretty tight fit biscuits but cuts with wen seem too big so biscuits wobble. am i missing something ?

After 2 uses the blade is burning the wood what causes this?

I'm a bit new to this. What's the difference btwn this product (or similar) and something like the Domino 500? I don't understand the price jump.

After receiving my biscuit jointer and making several test cuts, My biscuits just fall. Is there an adjustment to make a tighter slot?