OK, Hypothetical here as I hate how restrictive the rules have become through the years & yearn for the time when cars were competitive(I know this wasn't always the case) even though they looked different & had completely different design concepts. In my opinion side pod design (not the underbody/floor) should be a LOT more open to variance & design opportunity in the new 2021 rule set. I miss side radiator vents, chimneys, NACA ducts, etc. The Bennett B186 entire side pod of louvers, the Mclaren Mp4/15 Chimneys, all the various Ferrari side pod opening shapes. These were all examples of designers allowed to envision their own, creative solutions.
What would the side pods of the 2021 cars look like if above the new floors the only restriction was a dimensioned, rectangles box, starting from the entry to the floor, as high as the edge of the opening to the driver cell, as wide as the new floor dimensions allow & ending at the front edge of the back tire? Safety structures/spars stay as is. Anything allowed within this box. Aggressive side pod shapes, airflow openings, turning vanes, chimneys, vents, winglets, etc., All other rules stay the same.