Reset password

[hesyar]

Is there a way to reset or override the current user/password through environment variables?

[0x89g09sa823]

You mean admin account created in step "Thirdly, configure your Confluence yourself and fill it with a test license."?
If so, then it is not possible.
However if you lost your admin account credentials you can add -Datlassian.recovery.password=<your-password< env variable to access the instance. For more details see:
https://confluence.atlassian.com/doc/restore-passwords-to-recover-admin-user-rights-158390.html
Cheers,
Greg