In theory one can set any domain to "from" field, what about actual servers that sent the spam? How many of those spam emails have unsubscribe and/or complaint headers?
In theory the domain you set the "From:" field to will have DMARC, DKIM and SPF set up and in theory the recipient that implements those protocols will discard your mail as sent from an unauthorized server.
The spam emails pretty much ALL have unsubcribe headers now. I mean, they are all WORSE than useless since they are sending signal back to spammers, but Gmail is asking me to [Unsubscribe and Report Spam] anyway.