They give different results, it seems they have different treatment to the data, which is interesting. Startpage gives different results than google, duckduckgo gives different results than bing, but on the bigger picture, a bigger sample gives the statistically optimal result??? (closer to the source truth on the most probable good result) question mark, huge number theory on statistics.
(i'm drunk)
Bing and yahoo are VERY bad, it seems they detect that they are being used through proxies, I made another comment for what i use in searxng.
Bing on searxng is shit, yahoo ultimately is bad too, I use this combination, it helps a lot:
I run my instance using cloudflare tunnels, directly from my thinkpad (over wifi), these tunnels are helpful because you don't need to open ports, etc, also, there are other tunneling options, like hosting a server on a VPS that tunnels to your own selfhosted server, as there are some alternatives to cloudflare in that aspect.
Idk, might be an option.
Do Lemmy threads end up on search engines?
Probably yes, even if the instance blocks bots, they will go to another one to get the post, these ai bots are a curse on all instances.
In searxng they don't give the same results, bing brings some completely different stuff both on an selfhosted instance and on an public instance (it just gives random garbage), it seems proxying does some stuff to bings internal algorithm, as google is different than startpage on searxng.
Edit: a screenshot showing it.