Hi
Try either one of these
1. Use notepad to create a text file and type in :
# Use WinTab
UseSystemStylus 0
2. Save the file as PSUserConfig.txt in the following location
C: > Users > Username > AppData > Roaming > Adobe > Adobe Photoshop CC 2018 > Adobe Photoshop CC 2018 Settings
3. Go to the Wacom tablet properties and for Photoshop under Mapping uncheck "Use Windows Ink"
Or
1 Select everything inside the quotes here (don't include the quotes): “reg add HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Pen /v LegacyPenInteractionModel /t REG_DWORD /d 1 /f”
2 Copy it with Ctrl + C on the keyboard.
3 Type Windows Key + X (together), a menu will appear
4 Then type "A" on the keyboard. That will give you an elevated administrator PowerShell command prompt.
5 Paste the command you copied into that window with Ctrl + V
6 Hit "Enter" on the keyboard
7 Reboot