You can buy yourself a custom domain and add it to your hosting account and then to CloudFlare with a Free or Pro (etc) plan. Follow this guide to get CloudFlare set up:
Just don’t forget to change internal urls for Wordpress if you change the domain!
How could this be a PHP problem? It is your Wordpress, and if you think it’s too slow or whatnot, you can try to tweak it to make it faster. And if you don’t like how fast the php execution is on our servers, then upgrade to premium Wordpress hosting.
I use CloudFlare on my php site now, and I see a 200ms difference in loading on a CloudFlare domain vs a free subdomain.
So you come from China right? Well since this hosting service is not in China, It CANNOT be quick to get accessed. The only exception is to try to get access in the morning(GMT+8, best time 5am to 7am)(I know this since I’m also in China) which will work, but still, weird enough.
Also latency might be higher since people in Europe and USA have fast response times as servers are in the UK. From India the latency is normal, same as @wackyblackie