Ten years ago when DB engines were not as good and servers were not as large, I did something similar -- set up a trigger on insert/updates to certain relations

Ten years ago when DB engines were not as good and servers were not as large, I did something similar -- set up a trigger on insert/updates to certain relations that auto updates the main record with a cache column. Back then it was comma separated, but today I would obviously use JSONB. Back then it reduced latency significantly. Today, I would probably not attempt it.