I assume you mean you can see debris where the filter slides in?

Good news the inner plastic grille comes off with 2 screws (maybe 3) and you may be able to reach the area with a vacuum attachment of even by hand. Watch for sharp edges. Screws are inside the drum pointing toward the front going through the grille.

But for further access yes that bottom section of the front does come off, a few screws under bottom edge. That's give you access to the interior of the cabinet but not into the blower duct where the filter sits. For that area you need to pull the silver duct off that'll be behind the lower access panel.
I think you can access all the necessary screws to remove the duct from behind the access panel and just vacuum it out.

This video of the element change may help you visualize the task better. You'll see the blower duct at about 5:15-30. It's the silver piece with the gold colored screws. I don't think you'll have to take the top, front, etc off. Just the 3 gold screws that hold the duct onto the bulkhead and it'll slide down enough to come out without any further disassembly than the access panel. The filter will need to be out to remove duct, and the unit should definitely be unplugged or breaker opened for safety.

Whirlpool WP8544771 Heating Element - AppliancePartsPros.com