I am using both a professional Dell latitude laptop and a personal thinkpad on Fedora and both receive firmware updates. And I am pretty sure I saw the Dell USB-C docking station receiving updates through this too.
Not sure this applies also to non Latitude/Thinkpad consumer models though but I tend to never recommend them anyway.
I'm not a huge fan of the kind of laptops Dell sells with Linux on them (thin, poorly ventilated ultraportable donglebooks) or super loyal to the Dell brand or whatever.
However, I will say that their Linux laptops I've used have been fine executions of their concepts, and the Linux support, including for firmware updates, has been problem-free even though I don't run the stock OS.
They're a good choice for Linux laptops if thin and light ultraportables are your style.
Dell has a pretty good record for providing firmware updates without too much hassle. Although it does seem like they ship product with.. a lot of problems.
We bought a 10gbit enabled PowerConnect switch only to learn that the “10gbit” part didn’t actually work until they released a new firmware.
I got a Dell laptop from work with Windows on it. Installed Ubuntu and it immediately prompted me to update the firmware. What an amazing experience!
I always recommend Dell to people looking for a Linux laptop. Although I hear Lenovo started to get their shit together too in the last few years.