Now that Gmail introduced its new sending requirements, more people have been forced to implement some extra steps to improve their deliverability but here’s the kicker: It’s still not the full way to avoid people spoofing your domain.
First off, Gmail and Yahoo requirements apply to Gmail and Yahoo only for now.
Next, the main way to avoid your domain being spoofed is setting up DMARC with a ‘reject’ policy along with making sure you have SPF alignment.