It certainly could be your remote has just died. If new batteries, inserted in the correct orientation (easy mistake to make), don't get it functioning, you can check whether it's working by pointing it at a digital camera (the one in a phone or tablet will do) and pressing remote buttons while viewing on the camera screen. If the remote is sending infrared signals you should see flashes on the screen.
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Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X