If we had the finances of City or Chelsea then I think we would have signed Kabak as a 5th choice or even as an investment. As it is, I think the club has seen enough from Philipps in 2021 that he can do the job at a similar level to Kabak for much less cost.
Even now that Konate has been signed, I'd still be tempted to take a look at whether we could do deals for Phillips & Kabak at a similar price. I'd be inclined to keep Kabak around the squad until January as effectively our 5th choice (behind Gomez, Konate, Matip, and Van Dijk) and loan him out for a 10-15 game late-season stint if injuries are looking okay - consider him the long-term replacement for Matip.
Not that I don't see Phillips as being a decent player who's made a valuable contribution this season, but it seems generally accepted that Kabak has potential that he'll continue to develop through and that could serve us well for a long time whereas I don't get the impression anyone sees Phillips as a potential (choice) starter in 2/3 years time.