It might get 5.4 sometime, but it is probably sticking to the Longterm stable kernel release set like the rest of Debian Buster:

https://www.kernel.org/category/releases.html

it can actually work with 4.19 and the unstable repo. I'm using 4.19.105-v7+ (to solve a macvlan bug in the default .97 and it works. It's a pain to install the headers on raspbian though

That's what I've been doing, but I would like more official support for something as critical as VPN. I don't forward many ports across my NAT, so I really rely on the VPN to be rock solid. I am considering getting a second raspberry pi and running wireguard on two ports on two pis for redundancy (the ability to fix stuff after a bad update or me breaking something).

How does raspberry pi run on stock Ubuntu?

I am actually not sure. I know raspbian has modifications in it that take care of board specific issues in it, such as high power consumption/heat from some issue related to USB PD and/or power states. I am not too familiar with the inner workings of distros and how hardware-specific fixes are propagated, but I like the idea of sticking with officially supported OS/hardware combos for "set and forget" boxes.

Wireguard was too alluring to not try though, and now I really like it. I would like to move away from my homemade pull, build, and install scripts, but not for any good/justified reason. I suppose I just like the idea of someone being responsible for a software stack that I rely on.

YMMV, but I was able to get https://archlinuxarm.org/ running on my pis without too much head-scratching.

arch is on 5.5.6 as of 3/1/2020 (https://www.archlinux.org/download/), and it seems like the ARM porters are pretty good about keeping their project in sync (two day delay): http://de3.mirror.archlinuxarm.org/os/rpi/.

My best guess is that by April or May, Arch will do the minor version bump, and then a couple days later Arch ARM will get it.

It doesn't have the same hardware/software synergy that you like, but it might be a fun weekend experiment.

Arch is on 5.5.13 and has already been marked out of date: https://www.archlinux.org/packages/core/x86_64/linux/

I would guess that we'll get 5.6 in the coming days.

Interesting, can you cure my ignorance on why they don't claim to include 5.5.13 kernel in the main download page? I'm not super familiar with how distros are packaged up for consumers

Is the main download page the rough equivalent to `master`, and your link is like the feature branch for merging the latest kernel version into the distro?

The download page is for the monthly generated install isos, during the install process it will sync with repos and install the latest version

Thank you!

That makes perfect sense, actually: no sense crippling install the .iso with (potentially) unstable program versions, to stymie the install process.