Marcus, Michael, Mason, Maddox, Matthew,
^Maddox is a nice alternative
Zack?
Or: Felix Toby Hugo Fred Liam Rex Dexter Dean Sean Benji Luke
Zach
You could use the longer version maximus or maximilian and then call him max for short or another shortened version of those names, that way you still kind of get the name you really wanted
You could use the Welsh name Macsen - pronounced “max sen” or mason maybe?
Alex? It ends the same. Or Sam? Three letters.
Jax
If our best friend wasn’t a Miles would love that or Milo
Micah Milo Miles Maverick Knox