A few things:

An $850 bike is neither cheap nor low end. Probably 5% of riders have a bike that costs more than that.

There's absolutely no way to tell if $33 was fair/appropriate - we weren't there to see what was needed to tension, round and true the wheel, whether it needed a hub adjustment, was dirty, if the tire or rim strip was badly stuck to the rim, etc.

I don't understand people who don't get an estimate before dropping a bike off for repair.

As a former service manager I also don't understand a shop that does not voluntarily give an estimate. We always gave at least a range for every job, with a 10% allowance. Anything more than that and we would call the customer to explain the need for extra charges, unless we were told - "Do what's needed."