My employer uses Sentry for (backend) metrics collection so I had to unblock it to do my job. I wish Sentry would have separate infra for "operating on data collected by Sentry" and "submit every mouse click to Sentry" so I could block their mass surveillance and still do my job, but I suppose that would cut into their profit margins.
My current solution is a massive hack that breaks down every now and then.
Most organizations I've set Sentry up for tunnel the traffic through their own domain, since many blocking extensions block sentry requeats by default. Their own docs recommend it as well. All that to say, it's not trivial to fully block it and you were probably sending telemetry anyway even with the domain blocked.