You mean your single stream of HTTPS traffic to a known destination 24x7?

What if you only use the HTTPS VPN when necessary, e.g. for streaming Netflix (seeing that they've been a target before), but for regular browsing, email, DNS, etc. you don't?

There are enough differences between HTTPS and VPN protocols to be able to distinguish them using DPI. IDS/IPS vendors even show this as a feature usually.

There's protocols like stunnel that hide your arbitrary TCP traffic in a TLS tunnel that looks like web traffic.

Lack of DNS queries for one small example.

forge certs then mitm.