I don't know why but usually Caro-Kann players think that openings are a piece of cake and that its possible to always "come up" with good moves by just knowing rules of thumb. You have to see concrete calculation to check if its possible to get greedy or alternatively just brute-memorize the repertoire. If you are really curious then you can check it with an engine or ask L'Ami in the course forums
Taking on B2 with Queen in Advanced Caro Kann
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It's often ok to take on b2 once you've developed your knight (...Nb8-c6). Tip: Don't rush through the lines. Take notes in which positions you are struggling and go through them afterwards again to compare them and find out the subtle differences. It's a lifetime repertoire after all, no need to finish it in a month
The pre-computer heuristic about whether or not to take the b2 pawn was simple: "Even if it's good, don't do it!" There's a reason the b2 pawn was nicknamed the Poisoned Pawn (and the Poisoned Pawn Variation of the Najdorf was so named because black dared to take that Poisoned Pawn).
Nowadays engines have made everyone brave, some might say have made everyone foolhardy. On the one hand, just because an engine (or L'Ami) can snarf the pawn and run away, doesn't mean if you try it your queen will get out alive. On the other hand, a pawn is a pawn! As GM Larry Evans wrote, "He who wins a pawn and runs away, has a won endgame."
So, are you going to be brave and play like an engine?
I've been doing the lifetime repertoire of the Caro on Chessable. In many positions, after White develops their dark squared bishop, you place your queen on B6 to attack the B2 pawn. I'm having a great deal of difficulty recognizing when it's ok to take this pawn or not. I'm wondering if anyone knows a good heuristic for determining when to take or when it's too dangerous.