AC Infinity AIRTAP T4 Bronze, Register Booster Fan for 4” x 12” Vents, Thermostat Control Improves Heating & Cooling, Quiet 10-Speed Remote Control & Bluetooth App. ONLY FITS 4” x 12” Duct Openings

We had a similar issue, where our top floor was sweltering and the basement was frigid, no matter what we did with the vents and fans. The thing that finally fixed it for us was swapping out the upper vents for ones with fans in them: amazon.com/dp/B07H8R7X2M?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2 When it gets warm, the ones upstairs are put on full power, and that helps so much with the air flow in the house.

Something like this https://a.co/d/06UCRil4