you rather buy a new TV instead which can play 4K HEVC or FHD HEVC on its native/built-in media player via your HDD thru USB.
you will be upgrading your TV in the future, anyway. so might as well do it now, rather upgrade your NMT but use an old model TV which cannot support new video codecs... if it's a smart one, you could "stream" movies with it too!
btw, streaming movies online via Netflix, Iflix, Amazon, Youtube, etc. does not and will not damage your NMT nor your TV.. this is the new norm now -- that is, for those with really fast internet service =))