What's the ideal way to whiten a root canal tooth?

So a few years ago I had a root canal on one of my front two teeth. I still have my natural tooth structure- I was not offered a crown- and it's held up as well as the surrounding teeth. However, in the past year or so, the tooth has begun to yellow compared to surrounding teeth & doesn't photograph well. Bleaching didn't work well. What are my options? Veneers, lumineers, implant, crown? I'm nervous about getting that gumline gap I've seen with crowns.