The free edition of KPT Pen Lab. It adds a Pen Lab Basic tab to PowerPoint and a small helper app, KPT Pen Lab Basic.
Draw with the Pen, Rectangle, Ellipse and Line tools straight over your slide, move and adjust what you draw, and Place it as a native PowerPoint shape with your fill and stroke colour. Everything else is shown with a padlock: it is part of KPT Pen Lab ADVANCED.
If you also have KPT Pen Lab ADVANCED, leave it as it is: the two live side by side and share nothing. Apple silicon and Intel, macOS 13 or later.
If PowerPoint is open, quit and reopen it after installing.