I just had a look if psono would be for me. One thing that I discover all too often (and that is also the case here) is that SSO (openid Salm...) is considered enterprise (sorry for calling you out here right now, this is a general frustration).
If I selfhost i want to not have to manage all my services with individual logins. Selfhosting with e.g. Authentik to provide SSO and identity management is really a perfect solution, but alas so many projects lock SSO away in their enterprise edition (good on psono to not make it ridiculously expensive like often is the case).