An umbilical hernia is really common after pregnancy, especially if you have a diastasis.
Both issues occur due to weakened connective tissue and can often be confused.
A diastasis is characterised by the stretch and thinning out of the connective tissue along the midline of the tummy
A hernia occurs when a section of that connective tissue is weak enough to allow the abdominal contents (usually your intestine or bowel) to protrude through
A diastasis can be present all the way along the midline and is shown by areas of bulging which will feel squishy but won’t hurt.
A hernia is a small isolated area which may swell or bulge (an innie belly button may have become an outie) it can sometimes feel tender to touch.
Both issues can be made worse if your core is weak and unable to correctly manage intra abdominal pressure - remember this pressure will tend to seek the path of least resistance
Both issues can be made better by posture and alignment correction, breathing correction, core rehabilitation and core strengthening.
Exercising with a hernia or a diastasis is fine as long as you know how to use specific deep core engagement techniques to correctly manage the pressure that builds up due to the exercise.
Both hernia and diastasis can become more severe if you're exercising incorrectly.
Surgery can be an option for both diastasis and hernia if they become too server, or if the hernia becomes strangulated but in both cases surgery will only fix the symptoms not the cause - core weakness.
So the ultimate answer to fixing both issues is core rehabilitation and strengthening!