Variety. The variety of ways I can engage with the game.
Many Souls are about the master of moment-to-moment gameplay. And Elden Ring is also definitely one of them. I can now pretty confidently have a no-hit parry fight with a Crucible Knight or a Bell-Bearing Hunter. But Elden Ring is also about choosing between a myriad of options outside and before fights. Where do I go next? Why would I go there? And then choosing between all your options in your toolkit for a fight. There isn't one definitive best option. It all depends on what you have access to and your capabilities in moment-to-moment gameplay.
On the other hand, Elden Ring has now become my comfort game. I know it so well, and this immense game knowledge flows perfectly into my points above to make each playthrough, heck, each play session, a fun one.
I don't know how helpful my description of what draws me back to Elden Ring again and again is in serving as a tip? But maybe you can glean something from it.