Sorry, this was specifically about gubernatorial elections - unless you have some sort of weird state electoral college thing (which IIRC only exists in Mississippi and even there only sort-of), those are generally done with a statewide popular vote, and thus independent of district maps.
By creating barriers in certain districts it's going to disproportionally going to affect those people, for example long lines, changing someone's voting district, removing someone's registration. There are tons of ways.
No, gerrymandering is when you set up a district for the specific benefit of yourself. You should look it up. Stacking and packing are important terms.
My comments for examples of voter suppression
Edit: though gerrymandering is a form of voter suppression
the Florida state constitution requires a statewide vote to approve an amendment with 60% of the vote. If they couldn't get a governor elected they couldn't amend the constitution either.