Mine was very slow at first too… haha but not as slow as watching water dry with your site.
Two things – 1) Hosting could be poor 2) Theme can play a major role as well.
Besides that, in my case I have a fast host, and suppose to be fast theme or at least responsive – however I was still in yellow bottom and red. In my case I loaded website in wrong directory, the host moved it for me – it’s had all kinds of quirks that no one else has possibly due to a bad first install. Long story short – I got mine pretty fast on both mobile and desktop.
I used Cloudflare & litespeed together – I tried every plug in out there and tweaked for months with each one setting by setting. For me and my site with my theme & host that was the magic bullet – every theme and host varies so your mileage can vary.
Just Do one or two things at a time. PURGE, wait sometimes a day if things don’t seem like they did anything. I usually saw in minutes to an hour if a new setting was right for me but after a lot of changes – it took longer.
DONT be concerned with getting 100 perfect score – ONLY be concerned with the speed it loads.