Server load with Wordpress (Rest API)?

Question

Mobile development

Good afternoon, at the moment there is a working mobile application with a load of 7000+ users per day (or about 30,000 screen views per day), the application works completely offline, but due to a number of unavailable functionality + constant content updates, it has become very inconvenient to use. About 3 years ago, I tried to build an application online, it worked through the REST API on a regular hosting with a load of 100+ users per day, the hoster's technical support constantly cursed at the large number of server minutes used and the load, I had to look for an alternative and I remade it offline. I want to go back online, but I'm afraid that with such a load you need a good server (VPS) and the correct configuration of WordPress itself.

Can you please help with advice on what exactly should be emphasized when choosing a server? When setting up WP?
Or does it make no sense to go online and focus on offline? Thanks

Answer 1

The question is too general.
Well, the mentioned load should be pulled by the cheapest VPS.
The problem is that you have in WP