I have 6 weeks to prep for the 45 min meta interview...

I highly recommend starting off with this course which will help you establish mindset and set up a preparation schedule: Master The Data Structures And Algorithms Interview

After that, I recommend going through this course which explains the major data structures and algorithms concepts in-depth: Crash Course: Beginner Data Structures And Algorithms Concepts

Since you have limited time, I have 2 bigs pieces of advice:

1. Make studying a habit - As a parent, you will have a hard time finding huge focus blocks of 4+ hours. This means, you need to get value from random scattered 10-30 minute blocks throughout the day/week. Try to consume at least 1 course lesson or do 1 LeetCode problem every day, and it will add up incrementally over time.
2. Parallelize - If you are doing a chore that doesn't require high cognitive load (e.g. washing the dishes), you can treat a course as a podcast and listen to it in the meantime (Taro has mobile apps too to make this easier).

The good news is that 6 weeks is quite a lot of time. You mentioned 45 minutes, so I assume this is the initial round. I think this is very doable for you - A solid grasp of LeetCode Easy + Medium will give you a strong chance of passing this round.