I'm using Blender 2.8 but I cannot achieve to use the Wacom tablet pressure in sculpt mode like in other software. Is this a known bug?
Is your tablet's pressure sensitivity working in other applications? If not, here's a potential solution to the pressure sensitivity not working: https://www.drivereasy.com/knowledge/fixed-wacom-pen-pressure-not-working/
It says to go either go to search "Wacom Tablet Preference File Utility" open that application and click "remove all user preferences. Save your preferences then restart your computer.
You can also try updating your Wacom Driver.
I've noticed many people having problems with their tablet pressure sensitivity not working in Blender but working in other programs. I had the same problem and the solution was quite unusual. My graphics tablet (Huion Q11k) stopped working as soon as Blender lauches, unless I activate game mode. Game mode disables pressure sensitivity. The fix for me was not opening blender as a game in Steam. Disable game mode, then go to your steam library and get it to show SOFTWARE instead of games. Run Blender from the software tab instead and it should work.
For anyone still having this problem, I encountered the same problem a few minutes ago. I am using a Huion H610PRO tablet and Blender 2.91. I switched to Automatic as described above but it still did not work.
The solution I stumbled upon was simply based on the order in which both Blender and the tablet were started/connected. I disconnected the tablet and shut down Blender. Then I started Blender, allowing it to complete loading, and then reconnected the tablet. I hope it works for someone.
Looks like each of us has a different solution, I have a huion WH1409 and thought the problem was it but I forgot to activete pressure on "strength" AND "radius" I was going crazy, I don't know why it needs pressure on radius but I post it here if someone makes the same error.