When it comes to lines of text, there are tradeoffs between keeping longer words together, or splitting them up with hyphens & line breaks to better accommodate a consistent shape. Line breaks, hyphens, and controlling the offset percentages are all options to consider for special cases with typography like a shape with uneven edges or curves. What I might do in your situation is uncheck the default offsets checkbox in the object inspector under text positions, then tweak them a bit so that I can control the edges a bit better.
You can also allow hyphenation under the Format menu under Text. Hyphenation is disallowed by default, because for many diagrams it isn’t desired. With longer text, allowing hyphenation is one way to better wrap to the shape.
Here is an example, and notice that I have put in a hyphen to help my spacing, I have used control + enter to make a line break intentionally. In a case as custom as this one, some hand-tweaking is needed to get the desired visual look. I could break up the word “correction” using hyphens and I could also put the word “and” on the bottom line if I wanted to go further following the shape.
If we can help with some specific suggestions, drop our support humans an email with an example document from Help>Contact Omni & then choose Include Document.