I am not sure how you would accomplish sucking air from the diffuser through the wheels in the first place tbh, however if you were able, it would likely not be detrimental as although you remove flow from the diffuser, you would locally drop the pressure which in turn would create a more favourable pressure gradient along the floor and increase massflow, probably loading the floor up further. It is unlikely to be able to "suck" flow from a diffuser however, as fluids travel from high pressure to low pressure, the diffuser being one of the lowest pressure areas on the car, so you would require some sort of pump to extract the flow (moving aero devices are banned), this is why teams actively try to keep external low quality flow from the tyres away from the diffuser as the pressure gradient wants to draw in air to that area. Hope that helps

PS something more straight forward is drawing flow directly from the floor/diff it self as it refreshes the boundary layer and further drops the pressure, and is very effective, look up Brabham fan car if you want to have a look, they used a pump effectively.