Thanks for taking a look. Both are great platforms indeed. To my knowledge StrongDM is only connectivity, no passwordless authentication to downstream resources. We offer similar functionality to that of Teleport, but try to abstract complexity such as managing yaml files and manual configurations.
Infrastructure is only part of the story for us, as we offer SAML SSO, Password Vault, Radius, our own MFA.
Strongdm also has passwordless authentication to downstream [1]
Complexity is a relative term in this case. There is no complex yaml files when you want to setup simple SSH in teleport. The complexity arrives when you want to custom configure everything, which I think is same in your case.
I think both the solution solve this problem gracefully and has been around doing this.
[1] https://goteleport.com
[2] https://www.strongdm.com