While MX is for inbound smtp, there are some programs that will factor in whether or not mail is coming from a listed MX. It is usually a tiny fraction of the

While MX is for inbound smtp, there are some programs that will factor in whether or not mail is coming from a listed MX. It is usually a tiny fraction of the spam score though. In my opinion, it is totally fine to set your MX to wherever you want your mail to route. Ensure your outbound mail servers have matching forward and reverse DNS and that you have set up dmarc/spf correctly. If feasible, DKIM sign your outbound emails. A challenge of using your own MX can be if you then forward those emails to Google. The relays would need to be trusted for your domain and I don't know what options Google provides these days to whitelist the MX relays. Hopefully someone else here that relays to Google could chime in. If you want a more trusted/enterprise solution to relay emails, look into services like ProofPoint. That is their entire business. They will front the inbound and/or outbound email for a company and deal with scam links, spam, malware and other nonsense.