Which one is best for high-traffic websites: a VPS server or a dedicated server?
The fact is that everything depends not on whether it is a dedicated server or VPS, but on the configuration of a particular server.
Again, your question does not contain information about the specific load on the site, or at least about the frequency of visits.
Both VPS and a dedicated server can provide high performance with the right parameters. Both types of hosting have both their advantages and disadvantages.
This article well describes the advantages of VPS in comparison with a dedicated server,
but here it’s the other way around
To put it simply, then the dedicated server will be completely yours and you can rest assured that only you are using the resources of your server. Or, for example, you may not be afraid of DDoS attacks that are not directed at your site, but, for example, at your neighbor on the host server on the VPS.
Probably the most important thing when choosing hosting is choosing a hosting provider.