You see that is where you went wrong, this is a forum after all where people get asked questions and then try to figure out and resolve the issue for the person asking.
So to answer your issue:
Is it normal to have to be within 4ft of the TV, well no it's not normal however there could be multiple reasons for it.
To much sunlight causing interference with the signal
Cordless phones causing interference with the signal
Dying batteries
Dying remote
That is just some of them.
Now what you could do is buy a cheap one for all remote from Amazon and test it with your TV to see if you can do what you want it to do, seeing as most TV remotes now are not IR but Bluetooth instead, which is why the likes of the LG ones work at a greater distance, or whilst on a trampoline behind the couch in the next door neighbours kitchen
<< that last bit is sarcasm
If that cheap one for all remote resolves your issue then just stick with it, if not send it back and try a Fire Stick as those remotes are Bluetooth not IR iirc.
Before you ask "Why buy a stick when I have a smart tv" well because Amazon will update the Fire Stick for longer than Samsung will update the app's on the TV, not to mention the Samsung TV Software is utterly useless.
If you do decide to replace the TV, then send it back to the company you bought it from first and tell them what you cannot do with the remote, they will test and if it's actually a "Fault" they will fix it, if it's not then they will send it back.
You can then if you don't want it, throw it up on Fakebook or Ebay sell it cheap and put the money towards a slightly better TV from LG or Panasonic they are the only decent TV makers left now.