Hah. Got it.
I'll put this here in case it's useful for a future user.
Once again (as in the referenced question) I had to set a session-based environment variable:
>set ES_PATH_CONF=D:/apps/ElasticSearch/elasticsearch-8.6.2/config
Then:
D:\apps\ElasticSearch\elasticsearch-8.6.2\bin>elasticsearch-reset-password -u elastic interactive
This tool will reset the password of the [elastic] user to an autogenerated value.
The password will be printed in the console.
Please confirm that you would like to continue [y/N]y
Password for the [elastic] user successfully reset.
New value: YwP0X1n0Ym5KwOpXfojG
D:\apps\ElasticSearch\elasticsearch-8.6.2\bin>
... then got to the "you know, for search" at https://localhost:9500. Hurrah.