Samsung TVs run Tizen and LG TVs run webOS, and both platforms have their own app stores with IPTV players available directly, so you do not need a separate streaming box to watch on either brand. That is the main appeal: one fewer device, one fewer remote, and one fewer thing that can fail.
Installing on a Samsung Tizen TV
Open Samsung Apps from your TV's home screen and search for an IPTV player. Several established players are available directly in the Samsung store. Install it the normal way, open it, and choose your login method — Xtream Codes if you have a server address, username and password, or M3U if you have a single playlist URL. There is no sideloading on Tizen, so what is in the store is what you have to work with.
Installing on an LG webOS TV
The process on LG is the same in substance: open the LG Content Store, search for an IPTV player, install it, and log in with your credentials. webOS, like Tizen, does not support installing apps from outside its own store, so there is no APK step to worry about getting wrong.
If your TV's store does not have a player you want
Older Samsung and LG models sometimes have a smaller app selection than current ones, and a specific player you have used before might not be listed. In that case the realistic options are to use whichever capable player the store does offer, or add a separate streaming box — a Firestick or an Android TV box — which gives you the full range of players at the cost of one extra piece of hardware. The smart TV versus streaming box comparison goes through that trade-off properly, including the point at which an older smart TV's own hardware becomes the real limiting factor rather than its app store.
Entering credentials with a TV remote
Typing a server address, username and password with a TV remote is the most error-prone part of setup on any smart TV platform. Retype rather than paste where possible, double check case-sensitive characters, and if the app rejects your login, check first whether you selected the correct method — Xtream Codes versus M3U — for the credentials you were given, which is the single most common setup mistake.
What to do about stuttering playback
Both Tizen and webOS handle HD streams well on any TV from the last several years. If playback stutters specifically in 4K, that can be the TV's own processor rather than your connection, particularly on older models. Work through the buffering checklist to rule out your network first, since that is the more common and more fixable cause either way.