Signatures have never required cursive. Historically, people who couldn’t read or write would just put an X in the signature spot and that was valid. Yeah, there is a marginal benefit to physically signing something in cursive, but the purpose of signing it has always been more of a final agreement step.

If handwriting and spelling and how I signed it actually mattered at all legally, then I could sign a different name when I buy a car, get keys, drive away, and later in court, say “well I never agreed to pay for this car, look at my signature, it says Frank Sinatra”. Same goes for a true forgery. The evidence I didn’t sign it myself is my statement in court saying “I didn’t sign this”, and whatever signs there are that I didn’t benefit from this.