Frictionless way to connect to a user's Jira account via REST API

[Matt S]

I would like create an application that can use the Jira REST API.  I do not want to create a Jira plugin and I do not want to create UI within Jira. I simply want to access Jira data from application via the Jira REST API.

I would like anyone wishing to use my app with Jira to be able to authenticate via OAUTH and give my app permission to access their Jira projects.

I tested OAUTH by creating an "Application link" in my instance of Jira. However, it is not practical for me to ask every user of my application to create an Application link in their Jira instance. For example, I tried the same OAUTH flow with another Jira instance and received error "oauth_problem=consumer_key_unknown" because that instance did not create an Application link to my app.

I then tried Atlassian Connect and it seems with this method, my user would have to either "upload" an add-on or search for it in the add-on directory and add it that way. 

Are these the only way to access a user's Jira account?

Is it true that I either must ask every user to provide me with an API key created via their Atlassian ID or I must have every Jira instance create "Application links" settings for my application or manually add an add-on?

This doesn't seem like a practical way for me users to connect their Jira to my app. I do not want to use basic auth (I do not want to ask user for their password).

The Jira documentation is so verbose and redundant that I'm not sure if I'm missing an obvious thing here.