After yesterday update to 17.3 InDesign could not be started anymore

The OP's problem is already resolved. See this other discussion:

Seit dem heutigen Update von InDesign lässt sich die SW nicht mehr starten

Ing. Peter23788930l1hc, Jun 08, 2022
https://community.adobe.com/t5/indesign-discussions/seit-dem-heutigen-update-von-indesign-l%C3%A4sst-sich-die-sw-nicht-mehr-starten/td-p/12991762

Regards,
Uwe Laubender
( Adobe Community Professional )

having a similar problem. updated to 17.3 today and was unable to open InDesign anymore, when I had literally just opened it right before the update. the initializing popup would appear for a few seconds and then disappear, and then nothing would happen. i tried logging out and logging back in, which also didn't work. I'm also unable to install an older version because whenever I try, it tells me to close InDesign, which is not open. I have reset my preferences using both the shortcut and manually deleting them. I'm using Windows 11 also. 

It's hard to know what's going on

There's a few things you can try

Try resetting your preferences:
The easiest way to reset everything is to delete the InDesign preferences: as soon as InDesign starts to boot hold down Shift, Alt, Ctrl (and Apple/Cmd if working on a Macintosh). A dialog will appear asking to delete the InDesign Preferences, select 'Yes' on this dialog.
Further info and instructions here if needed:
https://helpx.adobe.com/in/indesign/kb/indesign-preferences-support-file-locations.html

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Reinstalling rarely fixes everything - you can do a complete reinstall using the
Creative Cloud Cleaner Tool https://helpx.adobe.com/creative-cloud/kb/cc-cleaner-tool-installation-problems.html

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Rollback to a previous InDeisgn version

https://helpx.adobe.com/download-install/using/install-previous-version.html#:~:text=Open%20the%20Creative%20Cloud%20desktop,down%20list%2C%20select%20Other%20Versions.