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

I think retail investors don't really need to memorize the process... just need to know roughly: the transaction you send may not be included in the block in the order you want, it might be adjusted by the "packagers" in the middle, the most common feeling is slippage, execution price, and occasionally being inexplicably front-run.
To put it simply, don't see yourself as competing on the same track as institutions; what you can mainly do is: avoid chasing hot trends with a quick impulse to place orders, try to use limit orders/low slippage, split orders, and wait until the chain isn't congested before acting.
But you can't ignore it completely, especially now with more and more ways of "private bundling" and "directly reaching builders," I’ll glance at the "anti-front-run/private send" switch in my wallet, and don’t arbitrarily raise fees— the more urgent you are, the easier you are to be exploited as a fat sheep.
By the way, I thought of the NFT royalty drama: on one hand, shouting that creators need income, and on the other hand, wanting to maximize secondary liquidity, but in the end, it’s all about fighting for the same cake—priority/order rights and settlement rights...
Anyway, my current mindset is, just understand enough to avoid pitfalls, don’t get stuck in the details.