License question: Self publish app for oculus, wmr and steamVR?

We want to self publish our design app which supports oculus, wmr and steamVR on our own website. We do not want to use the coresponding stores like oculus store and steam.

Do you have anyexperenice, if we need to make an agreement with oculus, valve etc. as we are using theire stuff (in unity), but not using theire store, e.g. pay royalties?

OpenVR (steamvr) is opensource and free to use. I don’t know about the other SDKs but we only use Steam and let they abstract the others