I feel like I probably saw even lower rated ones (below 5 stars) but off the top of my head rn:
https://www.mangago.me/read-manga/geimusho/
https://www.mangago.me/read-manga/the_rib_of_adam_jinmi/
This one always surprises me lol. Over 500 ppl hv rated it too.
Also this one-shot bl manga
https://www.mangago.me/read-manga/lord_of_the_ring/
Whats the lowest rated manga/manhwa uve seen on here?