WordPress can handle unlimited number of pages. It’s an open-source CMS so it would be against common sense to put hard limits on the number of posts.
Since you’re asking this I think you are stuggling with the performance of your site. Optimizing WordPress can be a challenging task, I’ll share some insights regarding that.
Number of Plugins on WordPress site
This is super important. I see too many sites with dozen of plugins who do nothing important.
It’s always a good rule to keep number of plugins to the bare minimum. And use plugins from the established authors and big user bases.
Essential WordPress plugins
Most important aspects of WP are:
Regarding Security the best plugin out there is Wordfence Security.
For SEO industry standard is Yoast SEO.
These 2 above are free but for speed best one is WP Rocket it’s a paid one.
Thing about speed is that you may even not need any plugin for that if your theme is very well optimized.
Some of the sharing plugins add huge delay in page load times. If you need sharing use some flat code, like pure html links instead of JS embeds.
Same thing for tracking, you shoud rely on 1 tracking system, and it’s even better if it’s tracking on server side.
Using shared hosting is not a good option here. It’s ok only if you’re in stage of development or testing. For production always use dedicated hosting.
There is a number of options here, I’ll list some popular options:
All of this options provide you with nice UI and a bunch of features. They use servers from providers like Google or AWS and bill you on top of that.
If you want more fair and transparent pricing you should try WPJack. With WPJack you can use servers from any provider, you pay flat fee based on your subscription plan. Servers are paid directly to server providers. In one WPJack account you can connect any number of server providers and manage all of them from the same panel.
Wellknown light WordPress Themes
Fancy themes with all of the bells and whistles are nice, but they’re bad for optimizing.
You should choose some light WordPress theme with good starting point. One of them is GeneratePress or official WP themes.