Check that you've not installed any other PS2 kext anywhere that would interfere with DrHurt's VoodooPS2Controller R6 (which is the correct kext to use on all E6x30). The kext worked perfectly on my E6220/E6230/E6440 under High Sierra and continues to do so on my E6230 under Mojave and Catalina. And I have the TouchPad PrefPane present too.
E6220 under High Sierra 10.13.6:
E6230 under Mojave 10.14.6 and Catalina GM (no longer runs HiSie):
Various gestures work properly, can't say they all do, especially as I have 2 left hands and big heavy fingers, but many do (show desktop, LaunchPad, Swipe between pages, ...).