Sump is just a nice place for hiding equipment, but not mandatory.And your tank definitely proves without question you don't need a sump
You don’t need a skimmer, but you’ll need to compensate with water changes. Either method is a cost. Salts more expensive.
You must have flow.
You must have light.
The AquaClear (or whatever HOB) just keeps particulate (uneaten food and poop) out of the water and is also a place to run a bag of carbon.
The trick is to keep the filter sponge clean.
A swapped out the sponge every week.