Would upgrading to the latest version of Postgres potentially solve the issue?
Potentially, yes, but the only one who can answer that for sure is you. Upgrade to 11.22 and re-run the query. Worst case scenario, it runs the same speed but you gained yourself a bunch of bugfixes and CVE resolutions. If the problem persists on 11.22, spin up a Postgres 16, load the data, and test it there.