I see that cosmos advertises running your apps on a vpn built-in. That might be worth looking into. When I switched to self-hosting everything on my “tailnet” and closed incoming ports, a lot of the nice features of Yunohost for maintaining DNS and certs for the various apps stopped being that useful. In this day and age, I think being able to self-host and experiment within a safe VPN environment instead of on the open internet is the way to go.