Than release it! Why do some developers feel so entitled these days? It's not going to cost you anything (being not for profit) and you already have it running in test flight.
What do you mean entitled? There IS a cost to releasing it. You don't release software to the public then forget about it. The software will need to be supported and updated. Each visionOS release, however minor, will need to be regression tested. Being a not for profit has nothing to do with it. Releasing the software will incur development costs in time and labor, and will affect their scheduling and support of all their other software versions.
I'm an AVP owner and software engineer, and while I'd like them to release their VLC native app, I can understand their decision to hold off until they have more of a user base to justify it.