Has anyone rented e-bike on korcula?

Nah, there are some pretty big hills. For riding to Lumbarda, it might be overkill but no worries if you’d prefer the boost.
Traffic can be heavy on the road out of town but otherwise light in my experience.

Yep, riding out to Lumbarda and the wineries over there made for a really nice day. There’s a place right in the center of town to rent from. There’s also a great view from the road above town.

This company might be helpful https://www.korculaexplorer.com/
They have ebike tours that we were looking into but we were a little late in the season. Maybe take a 1/2 day tour with them and then rent on your own.
They were helpful and responsive to my questions.