I manage multiple Starlink customer terminals, and yes, this is the level of support you'll get when there are issues. When it works, it's great, when it's down, you wait until it isn't.
I would recommend you keep that T-Mobile 5G home internet station as backup considering the price point ($35-$50/month) and 5 year price lock guarantee (as of this comment). Get a router that will load balance and failover between both that and Starlink.