Ancient-Red-Dragon: TVs usually have problems that make them not good for gaming on, i.e. low refresh rates, high response times, high input lag times, etc.
TVs have taken it into account for a long time that people play on them with e.g. gaming consoles.
For the "lag problems" there is usually already a PC or gaming mode in the TV which disables any postprocessing stuff on the picture which is normally the reason for the lag, or even if it doesn't, you can switch them off yourself.
Still, I guess a high-end gaming monitor with ultra-low response times etc. is better for (competitive) gaming, but modern TVs are generally quite suitable for gaming. If they weren't, lots of console gamers would be annoyed.
GeraltOfRivia_PL: Hey guys i am on 1920/1080 and why am wondering whether i should switch to playing on my TV (which i assume to be 4K)
Do you have powerful enough PC to run games at 4K resolutions? If not, you will not see any real benefit by playing your 1920x1080 games on a 4K TV (or monitor).