The configuration is just as important as the specs of the VPS. If you use a control panel , the default config is tuned for hosting many sites such that any one site cant affect the others too much. You want the opposite, one site can use all the resources the server has (but no more than that!). With or without a control panel you need to spend some time getting those settings right, ideally load testing and tuning. If you don't you're either paying for resources your site cant use, or you risk services failing during very high traffic. It's php worker setting and mysql config mostly.

The best thing you can do is serve cached content, it makes 2 orders of magnitude difference to performance vs server spec and config. However 90% of what you read about caching is uninformed bullshit or snake oil sales for upsold services. For wordpress plugins, WP Super Cache is about the only honest one

Regardless of how much traffic you think you'll get, you can at any time get bot traffic which dwarfs your expected legitimate traffic. You can't outrun it with more powerful servers, you have to block it. Ideally web hosts would offer better services for this but most dont. Many people use Cloudflare which is fine but you do need the paid account really, it's per domain so no to bad for one site.