I converted my 2 big sites to HTTPS about 10 days ago. So far super positive results. Maybe a 10% bump up. Doubt that the HTTPS conversion was a primary factor in the bump up, but I was worried rankings would tank and that is not so.
As part of the conversion I instituted a CSP (Content Security Policy) for both sites. I used a third-party service that catches all reports of HTTPS errors. Over the last 10 days I completely fixed any errors reported. Once you have those errors fixed, is there any reason to keep the CSP?
I'm of the school of "Any unnecessary thing you make a user's browser do, hurts the user experience.".