Lately I keep seeing people talk about block builders, bundles, and it feels like retail investors don't really need to turn themselves into semi-researchers.

All you need to know is: when you click confirm, the transaction isn't just "queuing to be on the chain"; someone will be packaging, someone will be cutting in line, being quick isn't as good as being able to slip a small note (roughly this is the idea).
So for me, a sufficient level is: don't sign randomly, don't open high slippage casually, don't dump a big order into a small pool all at once; if you really need to switch, do it in several times, and if you can use a reliable frontend, don't chase "faster and cheaper."
It's the same during airdrop season—task platforms acting like anti-witchcraft, making it feel like clocking in for work; everyone is waiting for confirmation, points, or a verdict...
Sometimes I also wait to figure things out: am I just farming for airdrops, or am I being led by the airdrops?
Anyway, no matter how cold the corner of the chain is, I don't want to be someone else's filler material.