18.04 I had a lot of trouble with on my XPS.

20.04 has worked like a dream! It even can update the bios now, so you don't need to keep a windows partition or usb around.

I really have no reason to go back to any other OS

What sort of trouble? I don't see that, though the only reason this system has Ubuntu and not Debian is that seemed necessary for hardware support initially, and I should move to that rather than Ubuntu 20. (In my experience it's brave to run a new Ubuntu within a few months of it coming out...)

Move to 20. The GUI is way faster, and I've had zero odd quirks with anything. Everything just works.

I replaced my older XPS with an Ubuntu 20.04 laptop from Star Lab systems. Mostly because I wanted firmware updates via apt-get. They have a new model coming out: better CPU, more RAM, more disk for the same price point as the XPS.

https://starlabs.systems/pages/labtop-mk-iv

The top-end XPS will be a more powerful system, but if you're gonna budget - worth considering. Build quality is excellent, have had no issues.

I don't understand the problem. I get microcode updates with apt and general firmware with fwupd (ready to install on next boot from UEFI). As far as I now that's the intended/supported procedure.

Compared to a MacBook Air how thin and lightweight this laptop is?

I have the older Stab Lab model (Mk III) and have never owned a MacBook Air, but Googling the newest versions of both:

Star LabTop Mk IV [1]:

Thickness: 0.58 inches (1.48 cm)

Weight: 2.2 pounds (1 kg)

MacBook Air [2]:

Thickness: 0.63 inch (1.61 cm)

Weight: 2.8 pounds (1.29 kg)

[1] https://starlabs.systems/pages/labtop-mk-iv-specification

[2] https://www.apple.com/macbook-air/specs/

Is there any distro with hardware video acceleration working in a web browser out of the box?

I tried installing Linux on my laptop but since watching videos is a major part of my laptop use case I can't really justify the switch.

Too bad XPS laptops seem capped at 32GB. Can get 64GB on Thinkpads.

Lots of people hate snaps though.