The process would be much easier using Oauth 2.0, which is natively supported by Power Automate, but for some reason Power Automate doesn't seem to be able to refresh NetSuite tokens and requires manual authentication every 60 minutes. So in my post I use Oauth 1.0 instead, which has no issues.
Thanks for the link. I took the concept and move more of the code into powershell to simplify the Flow pieces and make it a little more re-usable. With out your article, I wouldn't have figured it out, thanks!