Wordpress in it self is quite fast. If you use heavy plugins like elementor, it is going to use a-lot of resources because elementor makes 20-30 requests on single page hit which consumes a-lot of resource.
Builder and store plugins also make the wordpress slow. You should consider using as less plugins as possible. And, try to use cache.
If you have your own domain connected, try to use cloudflare to optimize the requests to your website. There are many other ways to optimize your wordpress website, you can search through forum or simply google.
Certain limits are defined like daily hits limit is 50000 hits. You can find more details about that here: Understanding Hits and Hits Limit
We cannot provide a definitive number of CPU and RAM resources as we have shared servers for providing the hosting services and it’s calculation is complicated.
No one is forcing you to shift to paid plan.
The above mentioned optimization techniques are quite basic and if you don’t optimize your website, it is going to hog the server and slow down the website even on paid hosting service.
You get with Profreehost the best possible server settings for a free hosting service. If you think your website has more resource requirements, you are free to use any other hosting service.