Playtested on a trackpad, noticed that mine doesn't have nearly enough sensitivity to allow to target and parry conveniently. I think that it's doable with the amount of buttons given if you rebind jump to E and parry to Space, and maybe use left Shift instead of right click (I assume it's the part that makes it hard for you?), but I myself really can't aim and press appropriate click nearly fast enough for what the game demands. Regarding too many controls, alas, the game's kinda meant for shuffling between a lot of buttons - it's in the genre of these hack-n-slashes.
Do you think something like double inputs or multi-button inputs would make it easier (i.e. pressing double direction to roll, or holding down attack to block) to play in your conditions? Could you tell a bit more about how exactly you play? I'm very curios what issue you ran into!
I didn't think of that configuration, that could work. The last config I tried involved trying to use my thumb on the trackpad and turning sensitivity way up. I had up arrow for jump and right shift for grapple, trying to have a more even distribution of work between hands. Double inputs would help with the configuring greatly, but honestly, I just need to get a mouse.