PS C:\Windows\System32> incus remote add my_cluster https://angstel.example.com:8443
Certificate fingerprint: f3a7079038205003c4806208104f643ade069877304ac647019c3455320d92a6
ok (y/n/[fingerprint])? y
Error: json: cannot unmarshal bool into Go struct field Server.config of type string
You’re getting that error when an Incus command line client is trying to talk to a LXD server which happens to have the core.trust_password configuration key set. Unset the configuration key and things should start behaving.
(There are a couple other potential keys but core.trust_password is the one 99.99% of the time)