we have open APIs for PSI. We can use that API explorer ,for same. One disadvantage is that, it doesnt reflect reporting in cool UI, the way we get in lighthouse.

Below links would be useful for same -

https://developers.google.com/speed/docs/insights/v5/get-started

https://developers.google.com/speed/docs/insights/v5/reference/pagespeedapi/runpagespeed