For (2), again it depends. Some companies build amazing things for cheap, some companies build crapshoot for tons of money. The trick is to find the sound you like for the cheapest price.
For (3), the simplest chain is the best(est) chain. I used to have a high-end 2x10 band eq which sat between pre and power stages. I removed it, and I'm happier. Unless I'm listening vinyl, I bypass loudness and tone circuits even.
There's a funny thing in audio. When you increase the resolution too much, the problems in old/remastered sources become apparent, and you can't enjoy that material anymore. A good Hi-Fi system is meant to create enjoyment, not motivation to spend more money on more equipment or sources.
Lastly, for casual listening, even the basic airpods provide plenty of resolution and detail.