Fedora 32 has wireguard. So does any rolling release distro. And for distros with older kernels there are loadable modules that retrofit it. Openwrt has had it for quite some time now.
Mikrotik users were requesting support of Wireguard since 2018 but Mikrotik didn't do it because Wireguard wasn't v1.0. At that time, wireguard.com listed dozen of OS/distributions you can use with wg.
Note this in the development tree not the stable release tree. No 7.x has not been released as stable yet and probably won't be for a while. The stable 6.x is still based on an ancient 3.X kernel.
I think it's more thanks to the fact that WireGuard recently got merged to upstream Linux, so all you need to do is to update the kernel and enable it in defconfig.
There are lots of stable Linux distros running the stable kernel which is 5.8. it is just distros like RHEL that call themselves stable, but are actually antiquated and honestly just give users a bad experience because most of the software is outdated. Wouldn't expect anything less from IBM.
And it's somewhat silly to freeze the kernel. The Linux kernel is meticulous about backwards compatibility. Spin up any distribution user space in docker, and watch it work.
Red Hat also customizes the kernel they've standardized on to disable hardware functionality which they do not want to support under SLA; they have two general ways of doing it, disable compilation of the entire module (where possible) or add the specific PCI ID to a filter-out on that module's supported hardware. The methods tend to route through a custom routine in their kernel patches which notify the user the hardware has been seen but will not function/be supported by their kernel.
This goes the other way around a well, they often cherry-pick new code and pull it back into their curated kernels to support the latest hardware offerings of their partners (Dell, HP, Broadcom, etc.) without pulling in possible unstable newer kernel code around it; they have contractors from those hardware companies assisting in the work to backport hardware module features.
I was never a fan of RHEL even before they got purchased. They've done some great things lately with Podman, Buildah, Skopeo, etc but never really been an innovator when it comes to desktop Linux. I see Arch and Alpine being the real innovators, and projects like wlroots.
So is Alpine Linux. Almost no enterprise I've worked at lately wants to deal with antiquated software as long as their Kubernetes distro is working well.
They provided a greatly improved package manager and package interface. Fedora and most other distros don't even come close in terms of the amount of high quality modern packages available from the official repos and AUR, but Alpine has also been growing substantially.
I guess there is some significant demand for it from Mikrotik's customers. I'll probably use it.