Firstly are we talking about sharpness, or do you mean resolution?
Being a former EOS system user and current LF and Hasselblad nut and 35mm RF convert heres my $0.02.
Depends which lens you use.
Sure a Canon L series prime lens will kick nine colours of s*** out of a pre 1980s Leica lens, but on the other hand a consumer zoom lens (i.e. 35-80mm 4.5-5.6) will pale when compared to the likes of a 1960-70s Canonet or even Russian Leica/Zeiss copy.
Carl Zeiss has done HUGE amounts of testing when it comes to things like sharpness versus resolution. If an image is too sharp your contrast blows out and you actually lose resolution. Sure if you blow up a 4mm by 5mm section of 35mm neg to 8x10 and compare the two results side by side with a loupe, the sharper lens will look better. But blow the whole negative upto an 8x10 picture, mount them on the wall, step back a meter then say which one looks best?
Sure the Schneider 300mm standard lens I use for the 8x10 is incredibly sharp, but I prefer the look of my 1890s design Carl Zeiss 80mm Planar on the Hasselblad.
A good article to read is Chapter 6 - 'Lens Shortcomings' of the LF bible (View Camera Technique by Leslie Stroebel). A book to read even if you're not a LF shooter. 9/10 times the theory will put you to sleep, the other one tenth will have you exclaiming "Hey, wow!" followed by the mad rush out the door with camera in tow.
On the other hand...
If you think your pictures are just plain 'fuzzy' and your focus and DOF is good, check for fungus on or inside your lens. This is common cause for 'fuzzy' pictures. Without film inside the camera, open the camera door, cover the light cell with some black tape, point the camera at a window or low wattage light blub and fire the camera. If you see what looks either a cloud or white specks/smudge, you've got fungus. Can be terminal if there's lots of fungus.
Another problem could be focus with your camera. Assuming you've got your eye in the 'golden zone' in your viewfinder (if you eye is off to either side, what looks to be in focus is actually not), your rangefinder could have been knocked out of alignment (ask any of the first Bessa R owners about that one). Unlike fungus, this can be fixed.
However... JD is right, if you want ultra sharp images, go 8x10. But then again they ain’t light and it takes about 5-10 minutes for three girls or two guys, or one brave luddite to set it up for a shot…
Stu 🙂