Hello and welcome to the forum
Am I right in assuming you’ve recently installed krita version 4.4.5?
Is your operating system Windoiws 10?
Before you downloaded and installed krita, were you using the Huion HS611 with the other graphics applications or did you get the HS611 after you started using krira?
Before you installed the latest Huion driver, did you uninstall any previous driver and/or other tablet drivers, making sure to disconnect the tablet, uninstall, full power off restart, install new driver, full power off restart, then connect the tablet?
Using the Huion driver setup/configuration utility, have you set up a separate application profile for krita?
I believe that the Huion driver utility has this ability and you should do that and select that profile when making changes there, for krita.
Now you have the ‘Use Pen Pressure’ button on the toolbar, make sure it does not have a little ‘x’ mark at its lower right. If it does, click it to make the ‘x’ go away so that pressure sensitivity is enabled.
When checking that pen pressure works, you should use the Basic-2 Opacity or the Basic-5 Size brush preset because these have simple and obvious variation of opacity or size with pressure variation.
For a more technical test, do Settings → Configure Krita → Tablet settings → Open Tablet Tester and you’ll get the Tablet Tester window that can be drag-resized for convenience.
Draw on the grid area and you’ll see the events log on the right side.
You should see lots of lines that look like this:
Stylus move X=111.55 Y=116.82 B=1 P=77.0% (DRAW)
P=xy.z% is the detected pessure signal at that time.
You should see that number vary as you vary the sytlus pressure.
What do you see in that list of tablet events?
If you’ve used Settings → Configure Krita → Tablet settings to select Windows Ink, did you make sure, using the Huion driver utility, that Windows Ink is enabled at the Huion driver end?