Hey @ir ,
Here are a few things to double check you are set up correctly.
These may seem obvious, but its surprising how we all over look small things sometimes.
- Texture Paint Mode, I can’t tell you how many times I have selected Vertex Paint or Weight Paint by mistake.
- The object you wish to paint on is selected before entering Texture Paint Mode.
- The Image Texture Node is selected (white border), and the correct image selected.
- The same Image is selected in the texture slot of the Tools and Workspace settings.

After checking these, if you still have an issue, let us know.