[NAME]  - Dell re-posted a direct link to an older Realtek driver v6.0.1.8248 for the XPS 8930 that doesn't cause the slow boot issue. Still unexplained by Dell went back two driver versions to one from 2019, when Realtek v6.0.9107.1 from 2021 also doesn't cause slow booting. FWIW, I'm using v6.0.9107.1 which was restored by rolling back the driver in Device Manager. So try rolling back it back in Device Manager, and if that doesn't install the right driver, manually download the one at the link above and install it yourself.
Greetings, Just wanting to share a funny experience which increased my windows boot time by 400% ( yes 4 times slower). Thanks to the use of Bootracer I am able to keep an eye on my PC boot times in quite detail like Bios, Windows , User logon and startup programs. The Windows boot time used to be around 20 s , but increased suddenly to 85 and sometimes 90 s. Looking at what happened just before the boot time increase I found the installation suggested by Dell Support Assist, of a new Realtec High Definition Audio driver (Realtek-High-Definition-Audio-Driver_PP3Y7_WIN_6.0.9205.1_A21.EXE) Rolling back to the 2020 Microsoft version solved the boot increase time issue. So newer is not always better and when it ain't broke, don't fix it. Unbelievable !  Francis
XPS 8930, Realtek audio driver 2021, slow boot