I can watch 4K videos from YouTube over my 100Mb Internet connection, no buffering. The initial start of the video has a hair bit of hesitation, like 1-3 seconds, but once the video is playing, I can jump to non-buffered parts of the timeline and it starts playing in less than 1 second.
4K UHD Bluray is 82Mb/s-128Mb/s. Jumbo-frames is not going to fix your 1,000Mb/s network not being able to handle 128Mb/s. Find the real bottleneck. It's probably the protocol being used to remotely stream the file. If you're using a web client, maybe your web service needs to have its IO buffers, network buffers, or caches tweaked.