If you turn off Windows Ink the Wacom Center or Wacom tablet properties, pressure sensitivity is lost in Photoshop. This is because Adobe Photoshop uses Microsoft Windows Ink rather than Wacom's native input by default. If you want (or need) to use Photoshop without Windows Ink enabled, you can disable Windows Ink for all applications, or as an application specific setting:
In Wacom Center, select your pen then choosing the "Advanced <" flyout menu on the right, and turn off the Windows Ink toggle switch.
In Wacom Tablet Properties, select your pen, then uncheck "Use Windows Ink" on the Mapping tab or the Calibrate tab, depending on whether you are on a Cintiq or an Intuos Pro.
To set this per application add the Application to the Pen by selecting the Pen in the tool list then click the "+" next to the Applications list, choose the running application or browse to the selected application to add it, then follow the same steps above to disable Windows Ink.
To force Photoshop to Use Wintab (Wacom's input method) instead of Windows Ink:
A single line text file named "PSUserConfig.txt" (case sensitive) needs to be added to the photoshop settings folder. Download here but right clicking on the link and selecting "Save as."
To access the settings folder press the Windows Key or click the Windows button in your task bar, type "run" then hit enter.
On the "Open" line of the run dialog, type "%appdata%" and press Enter. Open the Adobe Photoshop Settings folder, For each version of Photoshop you want to modify; e.g. "Adobe Photoshop year#\Adobe Photoshop year# Settings."
For example: "C:\Users\YourUsername\AppData\Roaming\Adobe\Adobe Photoshop 2025\Adobe Photoshop 2025 Settings"
Add the linked file to the settings folder, or create a new text file named "PSUserConfig" Open the new file and type "UseSystemStylus 0" then save the file.
Photoshop will need to be reopened for this setting to take effect. This should provide a smoother and more accurate pen experience in Photoshop, and alleviate a number of other pain points like straight lines at the beginning of strokes, and pixel level control on dials and sliders.
If you need to undo this change in the future, simply delete the new text file added to the folder.