Hmm, there's a bit of text-mangling.
Let's use https://explain.depesz.com.
PG13 LIMIT 1 : https://explain.depesz.com/s/GFki
PG13 no LIMIT: https://explain.depesz.com/s/U4vR
PG12 LIMIT 1 : https://explain.depesz.com/s/JAp4
--
Jonathan Chen <jonc(at)chen(dot)org(dot)nz>