I’ve used this but it made my laptop spontaneously reboot a few times (or was it a hard lockup that necessitated a reboot)? I liked it but ended up putting it away.

Dual GPU nvidia and integrated Intel, was running the latest Ubuntu LTS at the time with all updates.

And that's why it is best to avoid GPU-acceleration unless you truly need it.

GPU drivers have always been full of bugs and will always be, since modern GPUs are ridiculously complex and designed for speed rather than reliability.

eek what? That shouldn't happen on a modern OS, unless the cpu spiked so hot the computer decided the best course is a reboot.

Typically it's a RAM issue, or power stability issue or a graphics card issue/firmware causing instant reboots