While egg cups seem simple, actually they are not as easy as they look. In my experience, the deeper the hollowing, the more difficult. You might like to try some shallower hollowings, where it’s easier to ride the bevel.
As with everything in turning, practivlce makes perfect, just keep turning and suddenly ‘there it is’ and you’ve got it. As well as the video channel above, can I recommend an excellent video called understanding wood turning catches by Fine woodwork, really excellent explanations of why catches happen, and therefore how to avoid them.
If you really can’t get it, move onto something else, then go back after a few weeks, it may be better then. Let us know how you get on.