@rsvelko. I will work on some of the open issues for the D8/D9 version. I am using this module on my website (drupalabc.xyz). Based on my bandwidth, I might be able to spend 2-3 hour per week on issues in Login Destination.
I saw module looking for a new maintainer, that's why I created this issue. In case, you are actively looking at RTBC issues, I won't be needing maintainer access as of now.