You can't lift the restriction on twitter, it's built into the specifications; it's designed for "short status updates"; in which, according to them, is 150 characters.
I've been pushing for a "Biography" field in the profile page since UBB.Threads v7 was in the "idea" phase (it was in Classic, I tried to make sure every item that was useful in classic was in threads) but it wasn't deemed popular enough to add in.
And you know you love my picture
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