Doesn't seem so. First thing it asks is phone number. I assume they only added the option to share usernames instead of phone numbers.

True. To get a signal account you have to provide a phone number. You never have to share that number with contacts and signal seems to be pretty loose with accepting VOIP numbers. Regardless you shouldn't have to jump through hoops for privacy. #Signal is best for friends and family. #SimpleX for sensitive coms. You just have to work around the having to have contact with the person first in order to give them your QR