Recently, I keep seeing everyone complain that validators/miners are overfeeding, and that MEV is making the ordering unfair.

In fact, retail investors don't necessarily have to study "block builders, bundles" to the point of writing papers...
My basic understanding is: your transaction may not go directly into the block, it might be bundled into a bunch (bundle) for bidding and inserted;
someone might rearrange the order for arbitrage, resulting in larger slippage, even if you clicked first, it looks like you're a step behind.
Knowing this is enough for you to do two things:
don't rush in when liquidity is thin, use protective options if available (like private/anti-front-running routing),
split large orders into smaller ones, and leave an exit button for yourself.
Anyway, don't assume that "fair ordering" will automatically benefit you...
Tonight, I plan to check all the private sending switches on my commonly used trading tools, just start with that.