Cloudflare / WPEngine error 504 - DDOS?

It appears that a couple of our websites are being DDOS by competitors. We use WPEngine for hosting and originally had their ‘Advanced Network’.

So the sites go down intermittently with the error 504.

So this is where I’m a bit lost, there isn’t any traffic showing on the analytics in Cloudflare (traffic is proxied with for both A records and www CNAME).

I’ve switched the DNS back to legacy DNS which uses a Google DNS IP and I’m still not able to see any analytics on Cloudflare and Attack mode doesn’t appear to do anything).

Q1 ) Does this mean the advanced network is conflicting with my Cloudflare?
Q2) Could this 504 error an issue with WPEngine because they arent giving much away?
Q3) If Attack Mode is on, it should always show the interim splash screen when connecting a new session? as it doesn’t, does this mean its off still?
Q4) I have a professional Cloudflare subscription but there appears to be no way to submit a ticket, it only shows Community even though the on the prices page it said I can?

Thank you in advance.