Side channels aren't block cipher cryptanalysis. There's some very basic side channel stuff in Cryptopals, but modern side channel analysis is primarily microarchitectural, which is a significant change in focus, and someone should do a standalone resource on that.
Well it's very connected, you're using the knowledge about block cipher to attack them, even though it's not the "pure mathematical attack", it's still the most widespread attack against current cryptographic systems
That's not true, there are plenty of side-channel attacks that fall squarely within the realm of block cipher cryptanalysis. Examples include Differential Fault Analysis (DFA), Correlation Power Analysis (CPA) and more.
It's true that practical side-channel leaks on software block cipher implementations tend to be microarchitectural (e.g. cache timing), but that's only because the "easier" attacks are already mitigated or considered out of scope (e.g. no physical access).
