I have a USG Pro 4. Which is still purchasable from their website, not yet EOL, nominally still supported. The only firmware update in the last two years was to fix a security issue, and didn't include support for updated VPNs.
From my perspective, they have failed catastrophically to do what I perceive as the pivotally important parts of their job, without which the rest of it is pointless. So, while you say "Just stop", I say "Why the hell should this company be trusted with anything network-related, if they can't do bare-minimum-required security stuff?"
Release notes history is here: https://www.ui.com/download/software/usg-pro-4
The wireguard of which you speak is only available on their "next gen" gateways, ie, not the full set of gateways currently "supported": https://help.ui.com/hc/en-us/articles/12594825307927-UniFi-G...
It's now been three years since at least some of the forum threads started expressing concern: https://community.ui.com/questions/L2TP-unsecure-update-to-I...
From my perspective, they have failed catastrophically to do what I perceive as the pivotally important parts of their job, without which the rest of it is pointless. So, while you say "Just stop", I say "Why the hell should this company be trusted with anything network-related, if they can't do bare-minimum-required security stuff?"