Browsing to your site seems OK, Better than most.
Per the server header you are now using nginx and maybe using Apache previously?
Possibly that accounts for something being/seeming different.
Do you have test data confirming the difference?
I ran the Google PageSpeed Insights tool and out of 100 your site gives a
score of 82 on mobile and 92 on the desktop.
Given that, i do not see any speed issues that would affect your ranking.
Please run it yourself and see:
If you expand the Should fix and Consider fixing sections, there are some suggestions.
Hope that helps,