With no documents open (that will make any settings adjustments as your new default for any new documents moving forward), open your Swatches panel and select "Formatting affects text" then choose the default [Black] swatch. Any new text frames should now use that default [Black] swatch.
You can also reset your preference settings and that should fix your issues as well. It'll also set any other custom settings or workspaces back to default.
Ryan
This is more of an issue with your default settings that you can adjust. You may have accidentally set them to use registration black.
https://creativepro.com/setting-defaults-indesign/
With no documents open (that will make any settings adjustments as your new default for any new documents moving forward), open your Swatches panel and select "Formatting affects text" then choose the default [Black] swatch. Any new text frames should now use that default [Black] swatch.
You can also reset your preference settings and that should fix your issues as well. It'll also set any other custom settings or workspaces back to default.