On Motorsport.com Wache is quoted to admit that RB20 isn't living up to expectations in the high speed and that curb riding is still an issue, just as it was last year.
My guess is they overdid the anti-dive on the front suspension somewhat, didn't get the gains but got the disadvantages of such geometry. Mercedes if I recall correctly experimented in the pre-season test with a Red Bull esque aggressive anti-dive geometry but backed off a bit.
Edit:
RB20 is a better car than RB19 – however, maybe we could do a better job and that’s what we are trying to fix for the end of the season and for next year, to give the drivers a better tool to be able to fight.”
This quote makes me wonder if they indeed could introduce an updated front suspension at the end of the year. Maybe even the RB21 chassis. Sure, the viability is questionable especially under the budget cap. However, if they identified the root cause of their issues after Monaco and Imola, the timeline for a new chassis could be sufficiently long. We pretty much know Red Bull had a new chassis ready at some point around the Singapore Grand Prix a few years ago which they chose not to introduce. And regarding the budget cap aspect, Red Bull is the team most limited in WT and CFD hours, which ironically saves them some expense. Given that 2025 will basically be a continuation of the current car family, they might as well put their latest ideas to the test before the winter because next year they'll won't have much resources for the 2025 car.