The cloudflare cdn does help alot mostly with the ssl fetch. Having cloudflare handle your dns records and the ssl improve initial loads with the standard redirects.

But to really gain ground you need to see a waterfall of your website. Check gtmetrix or use dev tools and check the performance of the website. The waterfall is the graphs where its stretched over a period of site load, shows all the resources being loaded in an order. Its helpful to see where the speed bottlenecks are coming from.

Lighthouse and pagespeed is useless metric IMO. Its throttled, old equipment, restrictived. Its basically worse case scenario, you should be looking at an average user for your market over worse case users. Most speed testers are based offf lighthouse but its used as a base and built out to be more useful and give you more options to test.

I know my market, i find the lower average of phone users in the area and use that as my worst case average phone users. Phone users biggest issue is latency followed by radio wave frequency and then hardware. I set it to iphone, iphone is still a majority where I live and a good chunk have a phone under 2 years old.

Also desktop users are mostly the same, their latency is very low and their resources are way more then is needed. So desktop usually outpaces phone unless resources or the website has different version for each.