Elton John es EGOT

…kinda…
It would be like the Grand Slam if you replaced the Aussie Open with a pickleball tournament
Usually one of the awards (often the grammys) will be a reach like ‘best spoken word performance’
Emmys and Oscars obviously have the closest skill set overlap- but being a great stage performer (Tonys) doesn’t mean you can translate that to screen
BUT
If you’re a great musical theatre performer, you can obviously sing so a Grammy would be unsurprising

There's also the EGOT people who got an honorary and not a competitive award. So like James Earl Jones is technically in the EGOT club but he didn't win a competitive Oscar, it was a lifetime achievement award.

Also, his Grammy, while competitive, was for the spoken word category for an album called "Great American Documents" where a bunch of famous people just...read famous American documents like the Bill of Rights, Constitution, Emancipation Proclamation, etc.