GNU/Linux Debian Trixie Installing NVIDIA Quadro P600/P620 Driver Guide
How to Install NVIDIA Quadro P600/P620 Graphics Driver on Debian Trixie 13.x desktop – Step by step Tutorial.
The NVIDIA P600/P620 Debian 13 Driver Setup is Simple and involves just the execution of a few Basic Shell Commands.
Especially relevant: currently the NVIDIA 535+ Driver is not available in the Debian 13 Repos.
So here I propose as an available Solution the latest Generic Linux Driver build from NVIDIA.
Again in case of Installation Issue you should priorly see the Upgrade Kernel Guide.

GNU/Linux Debian 13 Quadro P600/P620 Driver Installation Guide