Pretty much this. If you don't want to pay Microsoft a subscription for extra security, your are free to build you infra from scratch using a 100% FOSS stack an

Pretty much this. If you don't want to pay Microsoft a subscription for extra security, your are free to build you infra from scratch using a 100% FOSS stack and do your own security over it including hiring dedicated security experts to keep on it 24/7. See how much that will cost you.