Did Amazon have the same constraints?
In my experience, GCP and AWS are within a tiny % of each other.
Then the reliability of GCP is a good bit higher. gp3 has 99.8% durability. I've seen several EBS volumes just disappear. Not deleted, just become permanently gone due to hardware failures. Compare that to 99.999% durability on GCP. You're spending several times for extra redundancy and complexity per gig on AWS just to come close to the durability to GCP.
If I have a choice between AWS and GCP, and unless I've got some specific product need for AWS, I'd probably go with GCP every time. It's such a better product IMO.
SADA (and their competitor DoIT) are just resellers. Support doesn't inherently go through them. That's a decision your company makes. It's generally not a great decision either, in my opinion, as those resellers add a lot of opacity between you and your cloud provider. Google recommends them because it's easier for them.
Yes, we all hate their support structure (it goes through SADA), but the price is right. At my last company with 4 engineers we were paying AWS ~$1000/month for support. At my current company back when we had a cloud service on GCP, we got weekly calls with support for $0/month. Folks at Google also seemed to approve my weird resource requests (tons of GPUs in the midst of a GPU shortage, etc.) without me going through any back channels. I didn't find it terrible to work with at all, and it was much cheaper than AWS.