MJ I’ve pert’near exhausted my collected knowledge of begonias with the above guess on the ID of your posted plant. Sorry.
Hopefully Laura735, a most excellent plant ID expert who Walter should be paying the big bucks, will tune in with some ID and care information. I saw where she had recommended the American Begonia Society to another person regarding his post. I visited that site and found it helpful. If your plant is a begonia it may be a type of Rex begonia. Check it out: https://www.begonias.org/greenhouse/rex.htm