Any TV with an HDMI port can be a modern streaming TV. Doesn't matter if it's from 2010. The smart TV software on most older sets is slow, unsupported, and missing apps. The fix is a streaming stick that plugs into HDMI and takes over completely.
The best options in 2025: Amazon Fire TV Stick 4K Max ($55), Roku Express ($25) or Roku Streaming Stick+ ($50), Google Chromecast with Google TV ($30). My recommendation for most people is a Fire Stick or Roku — they're fast, well-supported, and cheap to replace in a few years.
Plug it into HDMI, switch the TV input, connect to Wi-Fi, sign in to your streaming accounts. The whole process is under 15 minutes. The TV's original remote still works for power and volume; the streaming stick remote handles everything else.
One practical note: if the TV is in a spot with poor Wi-Fi, a Wi-Fi extender or MoCA adapter to get ethernet near the TV will dramatically improve streaming stability. A Fire Stick on 5GHz near a good router is nearly perfect; a Fire Stick on 2.4GHz in a basement two walls from the router is miserable.