If you are referring to YouTube in the previous comment, then yes, it is quite difficult due to encryption, etc., so may be better to use a lighter/ad-free client.
Have a look there, i would presume the actual layout and OS/software is the same as TVs that use the Roku OS like above. If the Roku streaming devices are the same as their TV OS, then quoting the above tv review link, "There are ads in the home menu, and there is no way to disable them", and programs like Pi-Hole will only go so far along with blocking certain DNS services on a router level which can impact the other devices.