Depending on your threat model, if you know your ISP is tracking everything, then a reputable VPN doesn't add risk. If you have guaranteed observation and recording at your ISP level, which is most people: then using a VPN, paid with cash or crypto, probably gives you more privacy. At worst case it's the same level of observation.

In your scenario, using a browser with encrypted hello, using fully encrypted DNS, the only thing the ISP would see is your connection to the web server. If that web server, like cloudflare, serves multiple things, then it may obscure who you're talking to.

That being said, if somebody is observing enough of the network, they can look at network traffic flows, and determine what other service you're actually speaking with. IE unique traffic patterns to play a game, watch a video, interact with a app. Those can get exposed by the size of packets and frequency of packets transiting.

The main difference between a VPN, and an encrypted socket, for traffic flow analysis, is the VPN traffic gets all lumped together, so a third party doesn't know which pattern belongs to which stream. So if you're streaming videos, well doing other stuff on the VPN, it becomes harder to identify your traffic flow.

The browser traffic flow analysis is much easier, because each individual stream of data is observable by the ISP.

The DNS traffic might be encrypted but that doesn’t mean that other protocols are. A VPN tunnel encrypts all traffic passing through regardless of protocol.

That "traffic between two IP addresse"s is enough reason to use a VPN you trust.

Put it this way, bit torrent traffic can be encrypted and routed over standard ports to make it look like regular web traffic, so still "just traffic between two IP addresses" but you wouldn't run that without a VPN, would you?

To add to what the others have said, a VPN requires one end to authenticate to the other. Regular HTTP and DNS connections don't.

If you need to access a service remotely, doing it over VPN requires the user to authenticate (to use the VPN).

If you simply expose the service publicly, even if the connection to it is encrypted, it doesn't prevent random strangers from accessing it or trying to break in.

In this case, a VPN only offers obscuring that you are connecting to the dns over http end point.