When the 'link' between Lightroom Classic and Photoshop has issues, the first step is to try this:
Use the Adobe Creative Cloud Application to uninstall Photoshop. When asked, keep preferences! After this reinstall Photoshop again.
If this doesn't help the nest step is to reinstall both apps Lightroom and Photoshop. Please folloe the steps below:
1. Open the Adobe Creative Cloud Desktop Client and uninstall both Photoshop and Lightroom Classic. When asked, keep preferences!
2. Install Photoshop first and then Lightroom Classic. The right order is very important here!
If this doesn't help try the reinstallation with removing the preferences also.
... Lately I used CCleaner 7 to remove duplicate files, and I suspect that this may have caused the issue.
...
By @jan_8902
My advice regarding such tools: Leave it and don't use such tools!! They usually do more harm than good.
My System: Intel i7-8700K - 64GB RAM - NVidia Geforce RTX 3060 - Windows 11 Pro 26H2 -- LR-Classic 15 - Photoshop 27 - Nik Collection 9 - PureRAW 6 - Topaz Photo AI