We recommend you do an upgrade to 2.10.9 first, then jump to 2.10.33+, though upgrade-planner says you could upgrade Ops Manager to v2.10.33+ from v2.10.2 directly. You will most likely experience downtime if you go straight to 2.10.33+ from 2.10.2-2.10.8 due to the warning posted on 2.10.33 (https://docs.pivotal.io/ops-manager/2-10/release-notes.html#2-10-33).
Also, you need to Apply Changes to all tiles with enabling the Upgrade all service instances errand as BOSH DNS Certificates Regeneration upgrade on v2.10.9 or later. https://docs.pivotal.io/ops-manager/2-10/jump-upgrades.html#bosh-dns-migration