Recently, the group has been discussing block builders and bundles again.

Basically, retail investors just need to know that "there's an intermediary layer that sorts transaction order, and you might get front-run or sandwich attacked."
Don't immediately push yourself to become a half-MEV researcher...
I personally remember three things:
Don't go all-in with large transactions on-chain (split into batches / limit slippage / use reliable routing),
Don't blindly trust a tool's "smart money" label,
Recently, some people have also been complaining that the label system is lagging or even can be misled;
And if you see abnormal activity on-chain, don't rush to follow, just treat it as noise and listen first.
The group chat atmosphere is quite genuine: half is about science education, half is about memes,
Anyway, just don't treat any KOL as an invincible golden ticket.