That being said, this is the first time I've ever seen an EULA be this brazen and predatory. Claiming that I'm not allowed to use the entire device because I don't agree to some post-sale contract? In writing? Are you sure you want to do that TCL?!?!?
It may depend on your jurisdiction but here in the USA, I'm pretty sure it's legal because they offer a full refund if you chose not to accept.
There are alternative ways to coerce users into playing along. For example, simply store/retrieve TV configuration in the cloud. Without connectivity configured, the TV starts over from scratch in device setup on every power up.
And connectivity obviously opens the possibility for other uses.
They offer you the opportunity to get a refund from the retailer, subject to that retailer's return policies, which may mean "open box" restocking fees, time limitations or similar.
That is not the same thing.
https://www.tcl.com/us/en/roku-tv/eula
“If you do not agree to this EULA, you do not have the right to use the Television or the Software. If you are within the allowable time period for returns under the applicable return policy, you may return the Television to your seller for a refund, subject to the terms of such return policy. You should perform a factory reset before you return it to erase data that may be stored on the Television.”