Some features that may help with this:
After opening the Shift-Command-5 screenshot interface, in the “Options” menu, you can change the folder your screenshots are saved to from the Desktop to any other folder of your choice. Files will still be saved, but you may find it easier to organize those files, as they will be separated from anything else on your Desktop.
After opening the Shift-Command-5 screenshot interface, in the “Options” menu, you can change the save location to Clipboard. Or when taking a screenshot with any other shortcut, you can save just that screenshot to the clipboard by also holding Control. Copying to the clipboard ensures there is nothing to clean up afterward.
If you want to take two screenshots and then paste both, you can still use the clipboard if you enable macOS’s clipboard history feature. That would let you copy both screenshots, then paste them both into your app. To enable clipboard history, see official docs at https://support.apple.com/guide/mac-help/search-your-clipboa... or a more detailed guide at https://www.cultofmac.com/how-to/mac-clipboard-history#enabl....