If you're looking for site speed assistance, it's always going to start with enabling LEAP and optimizing it properly, which includes disabling conflicting optimization plugins.
If you're not willing to compromise on that point, then we're most likely not going to be able to help you understand what's happening and how to improve scores.

It's worth pointing out that the 'score' you're referencing in the screenshot is irrelevant to the site ranking - only CWV metrics are used by Google, and they account for about 2% of all ranking factors. We don't optimize to a 'score' in PSI, but rather to passing CWV.