These emails are not always SPAM! Almost all my "emails from visitors" have been legit. They simply find me at FAA and contact me through there, since they do not know how else to contact me.
I have had lucrative commissions come from these "visitors". And just yesterday I had a ZOOM interview with a popular magazine from California who specializes in mid century modern. He found me at FAA.
So don't dismiss these "email from visitors" outright and assume they are SPAM. The vast majority of mine have not been SPAM but legitimate requests for commissions, or businesses looking to buy wholesale for their brick and mortar shops, etc.
PS, I wanted to add that the handful of SPAM ones I have received have not mentioned my name, they typically say "HI! I love your art!"... So that is one clue that it is indeed spam, if they do not personalize it and mention you by name. It generally means they have sent you and others that same message.