Many TVs have wifi problems because the antenna is behind the screen and backs up to the wall. It is a poor design, but..... As a test, you could try using wifi on a phone held behind the TV to see if the signal falls off badly.
Without reference to your particular TV, here are some ideas. Temporarily move your access point/router and TV as close as possible. If that works then re-position the equipment as best you can to maintain a connection. If the equipment must be positioned so the wifi is weak, then use the Ethernet port on the TV. Either trough a direct Ethernet wire (the best) or bridging through a wifi or powerline adapters. You can also check if the manufacturer has a wifi dongle that will plug into the TV in a better location.
There may be others that have recommendations specific to your TV, but if you need to buy bridging adapters, make sure you do so from a store with a good return policy and return them if it doesn't resolve your situation. That is what returns are for.