External GPU for 2013 MacBook Pro - Samsung 4K / 55" TV

Hello -

We have a 2013 MacBook Pro Retina and are having trouble with our direct HDMI connection to a 55", Samsung 4K TV. Under higher resolutions when viewing Sketchup models, rotating, zooming, etc. is painfully slow. Would an external GPU be the answer to our problems? Any other suggestions?

I googled eGPU’s and it seems that there are few options for the Mac.

Thanks for any advice you may offer.