Just For Your Information
... I have try to create kernel modules (wireguard) for ADM 4, the problem is for x86_64 the kernel version used by Asustor : 5.4.x, also require to used compatible modules and not in tree.
The problem for compatible module is the check of kernel version, based on calculation to compare value ... and "x" is not a number.
If Asustor provide the good environment for kernel tree modules (G.P.L.) source with modification to accept the x, it's not the same for other modules when they used this verification internally., or for some program, for ex. strace "original" not working up to they add the support for malformed (it's the term use by strace dev. team) kernel version (issue I report to dev. on github)
I have others project, so I stop testing ... but if I have time, and if Asustor don't create it in a next delivery of A.D.M. ... I will redo some try.
The problem for Asustor (I suppose) is that it's difficult to create a WebUI interface, because, this require (if you don't want to configure blind) a simultaneous access to server and client to exchange keys. and run tests ... so the integration in A.D.M. is a little more difficult for non confirmed in Linux users.
Please, remember, I am not an expert ... it's just my two cents.
Philippe.