For basic Bass / Treble boost or cut, you can use the Bass and Treble effect, which has “real-time preview”.
See: http://manual.audacityteam.org/man/bass_and_treble.html
There are various VST equalizers available as free downloads from the net. Audacity supports real-time preview for VST effects.
I don’t use Windows, but see this post: https://forum.audacityteam.org/t/using-eq/46139/3
and this one: https://forum.audacityteam.org/t/version-2-1-1-0-doesnt-remember-equalization/39205/7
and this one: https://forum.audacityteam.org/t/version-2-1-1-0-doesnt-remember-equalization/39205/5