Hello,
I have a the same/problem question. But my knowledge is too limited to find how to fix it. The server running cryosparc should have all requests directed http to https for few ports (https://certbot.eff.org/lets-encrypt/ubuntubionic-apache). But somehow it does not work for cryosparc.
Being able to use the web interface without vpn or ssh tunnel is brilliant but it should be https indeed.
Not sure/convinced the nginx is the answer and I don’t know how to configure it.