I want to know how to remove, deactivate, or cancel my Spans quota, or otherwise opt out of Tracing so spans stop counting against my plan.

No. You cannot disable or remove the Spans quota from your Sentry subscription. Spans are included on all plans, so there is no in-app setting to remove this quota.

If you want to stop Tracing and prevent span volume from being consumed, disable tracing in your application SDKs. Open the Set Up Tracing docs for your SDK and remove tracing configuration from initialization, such as tracesSampleRate, tracesSampler, and tracing integrations. There is no organization- or project-level UI toggle. See Can I globally enable or disable tracing?.

Note that setting a traces sample rate to 0 may not stop all span traffic. See Why changing my traces sample rate does not affect the amount of transactions sent to Sentry?.

If you want to keep Tracing but reduce the number of spans, use sampling and the other controls described in Manage Your Span Quota.