What to do if you can't get sound from any other applications while Ableton is launched.
15 August 2023

Download driver here.
Since this is no GUI driver create manually file named FlexASIO.toml
in location C:\Users\%USERNAME%\FlexASIO.toml
Put there something like this:
backend = "Windows WASAPI"
bufferSizeSamples = 512
[input]
# Disable the input if you only play VSTs.
device = ""
[output]
# Set the output to WASAPI Shared Mode,
# true for Exclusive with less latency
wasapiExclusiveMode = false
or follow instrunctions here
Keep bufferSizeSamples
at higher values (512 or more) if you want to avoid flickering during mixing large scale tracks.
wasapiExclusiveMode=true
could result in lower latency, but I belive you'll loose possibility to launch another audio source beside Ableton.