You can start a presentation automatically at startup. First, time and save your presentation as a PowerPoint show (*.ppsx).
Click the Record tab, choose the Record button and click on From the beginning. Or go to the Slide Show tab, click Record slide show button and click Record from beginning.
Press the red record button and then click on the right arrow to move to the next animation or slide.
Save the presentation as a slide show.
Then put the ppsx in the Windows 10/11 Startup folder. You can find the folder here:
C:\Users\User\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup