Well Andretti applied to the FIA regarding fielding a new team from 2024, Andretti Global has met all the financial and resource requirements so its really a matter of the FIA giving the green light. Mario and Michael also started a special purpose acquisition company, which coincidentally has raised the exact amount that is needed for the $200mil entry fee.
As for Redbull and Audi/VW, VAG has been dangling this carrot of "entering F1" in front of us for well over a decade. The soonest we'd potentially see them in F1 will be when they have the next gen hybrid power units, slated for 2025. I think with the planned simplification of the hybrid units, it will probably draw them and/or maybe someone like Cosworth in.