I haven't needed to contact support, but I think they have a manned tech support email address too.
Also, unfortunately Gmail/Gsuite is very cost-effective for us. We've looked at ProtonMail which seemed nice and potentially worth supporting but they would have cost us probably ten times or more what Gsuite costs (for email service only!) thanks to having to buy a ton of add-ons to get feature parity (they actually do charge extra for pretty much each custom domain and alias you want to use). And buying 100 GB of storage costs an eye-watering $120/month ($1.99 on Gsuite). I really don't know why their pricing is so weird. I know they can't probably scale as well on storage but adding aliases does not cause any measurable additional cost for them...
Anyway, if anyone decides to make a Gmail UI clone with a reasonable spam filter and pricing that's at most 2x what Google charges: Please let me know, I will migrate 120 new users to you within a couple weeks (not much on a grand scale but it's what I can offer...) :-)