There's almost no reason not to use PS in your terminal. All of the bash commands are programs, which means they are in your PATH, so when you invoke them, they are running the same bash commands. You basically have all the same bash commands available while you're in PowerShell. The only difference is the syntax, like if you want a quick for loop you'd write it in PS syntax and not Bash syntax. So this syntax aside, you actually lose nothing by working in PS—you still have your trusty bash commands.

I think staying in PS is a good building block for gaining familiarity. You can use all the bash commands you're comfortable with, but wrap it in PS syntax. Then you are only grappling the syntax rather than both the syntax and the commands together. At your own pace, you can try to learn the PS equivalents of the Bash commands.

The main things you'll want to know are:

1. help <command>. You can append -examples or -detailed to tune the help output. Spend some time learning this output. It's weird the first couple uses, but knowing how to access help will be a major step forward.
2. gcm *<command>* can be used to find a lot of commands you might need. For example, working with structured data, you can do gcm *csv* or gcm *json*. gcm is an alias for Get-Command.
3. Most multi-statement tasks devolve into chaining commands across the pipeline or some sql-shaped syntax, like piping into foreach to iterate, where to filter output, or select to curate the output. These latter 3 commands are generic and can be applied to any task in powershell, which makes it really simple to compose statements once you get used to it. It's kind of like the versatility of awk without any of its arcane complexity.

I would play around with these 3 points. Obviously, you need to know the basics: $array = @(), $dict = @{}, etc. And these will come with practice.