be happy if it runs stable on Fedora and 4.19.x at all, that's here not the case even with WS
but your question is pretty dumb in a long term - just because *now* you are lcuky that it works with the newest kernel does not mean the same for 4.20, 4.21 and so on as well as nobody but you knows why you have to delete with WS15 created VMs to continue running with 14.x - it's your choice in which compatibility mode you create a VM and when younning trails where you are not sure if you ever upgrade and set it to 15 is, well, dumb