You could use a Regular Expression to validate more specifics like requiring a space and certain characters in the beginning of a value.
This site has a lot of regular expressions you can probably search and find the one you want if you don't know how to write your own:
https://regexlib.com/?AspxAutoDetectCookieSupport=1
You could implement reCaptcha v3... That is an invisible captcha option that doesn't require the user to do anything.