After I switched from Nvidia to AMD GPUs on my main rig, I can now run Sid without issue and upgrade my Kernel whenever I want to without getting a black screen with a blinking cursor on the next boot.
Are you refusing to use the Nvidia binary drivers and/or a setup like DKMS that ensures kernel modules are rebuilt as necessary? While I respect the principle, it's a problem you're creating for yourself.
> upgrade my Kernel whenever I want to without getting a black screen with a blinking cursor on the next boot.
I installed the drivers according https://wiki.debian.org/NvidiaGraphicsDrivers. Yet every time a new kernel is released (note that this is new, new kernels, e.g. at the moment I am using 7.0.10, just one point release off the current tippy tip 7.0.11), whether or not Nvidia drivers would work after boot was a crapshoot. Maybe it's better now, seeing as they are trying to open source some part of the drivers, I guess. It got so troublesome at the time that I just got a 7800XT to replace my old 2070. Never had the issue again.