Clients sending email via gmail

So, recently I've discovered that some of my clients prefer to setup their gmail with their POP email accounts from our dedicated servers. This is fine, and works great except the emails fail SPF checks and are all ending up in spam. It appears google wants hosts to add their google domain to SPF records: ( include:_spf.google.com -all ) The process is vaguely outlined here: It only specifically mentions Google Workspace clients, but I believe that record is for all google mail senders. Anyways, I have a couple of questions for anyone who has been down this path: Is my syntax correct, to just add that to all related domains SPF records? Is there any downside to this? Do other mail services have issue handling the two records? Will SPF alone be sufficient to avoid spam? Or do I also need to add google as a possible sender in DKIM records?