Lately, I keep hearing people talk about blockchain builders, bundles, MEV, and so on.

Honestly, retail investors really don't need to turn themselves into researchers...
I think knowing three things is enough:
The transactions you send on-chain may not be included in blocks in the order you see;
Large or popular pools are more likely to be front-run;
Don't randomly click on those unfamiliar frontends claiming to guarantee the best routing.

As for bundles, just think of them as "someone packs a series of transactions together and also arranges the order clearly."
Just focus on the outcome: setting slippage too tight can cause transactions to get stuck, setting it too loose can get you front-run;
During peak times, try to use reliable wallets with anti-front-running or private sending (enable if available).
If you're not chasing short-term trades with dozens of transactions per second, you probably won't get tormented by it.

Recently, social mining and fan tokens have also been quite noisy.
Attention indeed can be used as fuel, but I always feel most of the time it's just exchanging attention for points...
Anyway, I prefer to save my energy for clearer entry points and then take a look.