The short answer is yes, and the useful answer is: match the things people type, and stop worrying about the rest.
What people actually type
Almost nobody types a social handle from memory. They tap a link, or they search your name. What they do type is your domain — into an address bar, into an email, onto a form. That's the one that has to be obvious.
Where a mismatch costs you
- When your domain and your main platform disagree, every piece of print has to carry both.
- When someone guesses your handle from your domain and lands on somebody else's account.
- When you outgrow one platform and the name doesn't travel.
Where it doesn't
A different handle on a platform you post to twice a year is not a brand problem. Neither is a Reddit account that doesn't match — nobody expected it to.
A workable standard
Get the domain and your one or two main platforms to agree exactly. Everywhere else, get as close as the platform allows and move on.