Over the years I have had boxes and TV's with many options to connect to many systems from BBC iplayer to Utube, the problem has been although they may work when bought, then the rules change, so they no longer work.
However it does not matter what the main use of the device is, the internet option is normally an extra, be it a sky+ HD or a free to air HD box, or a blueray player, or a DVD recorder, the internet is an extra. There are boxes today designed to receive internet content, but not actually designed for Utube, that is still an extra.
So I went to find a box for my mother to watch old black and white films on Utube as she liked talking pictures that much, the first unit I got was from PC World, however when I came to use it, it required me to enter in my bank details before it would do a thing, and there was no way I was entering my bank details so a woman with alzheimer's disease could run up a huge bill in error. So I returned it and went to Maplin, the free to air satellite box worked for about a year, then some change resulted in loss of internet channels. Still works with satellite, but not internet.
Then the first of three TV's with internet, one was smashed with a vacuum cleaner when the handle fall hitting screen, but other two have continued to work with internet and Utube, one also has free to air satellite although rather poor with many channels missing, but Freeview and internet may be received on the same device, but they are not connected.
My new laptop has HDMI so the best way to watch Utube is likely an old laptop plugged into TV. If you give make and model it is possible you can watch Utube direct. But if you want a time tested method, then the PC is best option.