Here's the colormap I use, which I've made sure never has too-bright colors on the near-white background: https://pastebin.com/raw/AdR3sBSs
Microsoft publish a tool in the Windows Terminal GitHub repo, ColorTool.exe[1], which can turn iTerm2 color scheme files into Windows Terminal ones. That might be your best bet because there are huge repositories of good iTerm2 schemes[2] and really slick tools to quickly make your own with live previews.[3]