In #78418, we addressed #75449 by using a parallelism of 1 when running IMPORT in multi-tenant mode. We set numNodes to 1 because we don't support DistSQL for IMPORTs in multi-tenant mode. Longer-term, however, we'll want an API which allows tenants to query the number of DistSQL pods available for these types of IMPORT jobs.
Jira issue: CRDB-14466
Epic CRDB-18499