Last week , I also tried using getnvidia in BookwormPup64 10.0.6 , kernel 6.1.76 without success.
I also tried to use apt but it kept saying that nouveau was still in use so .... no driver .
Then I tried to boot without X , with prefix=nox , having wired internet and then , I updated apt on command line , after that
using apt I installed nvidia-driver and nvidia settings only . It installed the 525.147.05-7 .
I didn't know anything about " libnvidia-cfg1 nvidia-xconfig && nvidia-xconfig " . Thank's for sharing @dimkr & @bigpup 
But , I had enter xorgwizard , chose manually nvidia as driver , chose my monitor's resolution and 24bit colours
and in the end xwin , and I got a working desktop , driver and Nvidia settings software working . After RestartX , several times ,
the desktop came back with the Nvidia driver still working .
By the way , my card is RTX 4060 .
In cases like this I usually do a remaster to keep the changes .
I tried three times to remaster but had no success in keeping a functional working desktop with the nvidia driver in the remasterd sfs .
I don't know if this was because of the overlays file system or not . I need to learn more about it .
Thank everybody for sharing .
Edit on 25-03-2024 : Today , with a working Nvidia driver installed like I mentioned above , I found a workaround for keeping the changes .
I don't usually use a savefile , but now I tried and managed to save to a folder . Later , after reboot , I used nicOs-Utility-Suite and made a sfs out of the save-folder ,
renaming it ydrv .