If you mean that it is dropping wifi signals during different uses (each time you turn on tv, you are finding that it is no longer connected to network) then try enabling the Fast TV Start option in your settings.
SETTINGS...SYSTEM.....POWER.....FAST TV START....Enable
Then do a System Restart. (Located in same Settings Subset under POWER)
This normally stops the dropped network issue between uses.
If you are having different issues like during streaming, drops out, loses internet, etc. need a little more detail in your question. Hope it helps you.
Roku Community Streaming Expert Just another Roku user... I am not a Roku employee. Insigna RokuTV, Ultra 4660x, Premiere+ 3921, Express 4k+ 3941
@Skyslimit45 , I have two Roku TVs which have never had any network problems. (They are disconnected from the network now due to Roku's software updates being untested, breaking things. In my case, antenna tv took a very bad hit. But, for the year they were connected, no problems.).
If you have a dual-band router, I would ensure the tv is connecting to 5g. Unless you're in a large house and the tv is a long distance away, then maybe 2.4g would be better. If using 2.4g, maybe the channel your router uses is congested by neighbors.
One of my tvs would not connect to 5g when I had my router set to smart-connect (one wifi name; some kind of magic negotiates whether a device gets 5g or 2.4g). When I turned that off, and created specific access point names to connect to, it connected to 5g.
I've seen some people say that some "secret screen" changes (disable pings & BT something or other) fixed their network woes. I don't think we're supposed to talk about that much. You can google for the remote key presses to access that.
Your topic title asks if there is a difference between external Roku devices and licensed TVs. I would say there's a very obvious different. It seems like the licensing scheme has not adequately addressed the plethora of hardware rising from 15 brands, dozens of models, revisions within models. It looks like a trainwreck to me.
If it were me, I would return the tv while I can. Maybe get an Android TV since that's what Roku wanted to be (but doesn't seem credible). Or, factory reset it without network connectivity (a dumb tv with original/limited software) and stream externally using whatever device you want. Even if you get this wifi problem working, you're just one untested update away from disaster.
This does seem different than the external streaming devices. In those cases, Roku has a specific hardware design it's responsible for. Less anarchy to deal with. So, I would say return it and get out while you can. But, if you like the tv picture. If you got it at a good price. Make it dumb for its own good.
"People are often amazed at how much we’ve done with the number of engineers we’ve got." (Roku CEO Anthony Wood, Austin Statesman, Oct 4, 2019). "Amazed" is one way of putting it.