When I analyzed the site it gave me 3 warnings and 5 failed tests, what bothers me the most is this
Your page makes 38 requests. More than 20 requests can result in slow page loading.
total: 38
images: 4
javascript: 21
stylesheets: 13
Thank you for contacting Rank Math, and sorry for any inconvenience caused.
Request are usually files you include on your page, this may contain tags, images and etc. You can reduce this number of requests on your page as they affect the loading speed of the page. I think you will find really useful (and detailed) with this one: https://onlinemediamasters.com/why-is-wordpress-so-slow/
Please note that the score is there only for your reference anyway and doesn’t affect your actual rankings. Treat it only as a to-do list, nothing more. Don’t try to live by it and don’t follow the tests religiously.
Hope that helps and please do not hesitate to let us know if you need our assistance with anything else.