I was under the impression 많이 was "many" and 너무 was "very", or are they interchangeable sometimes?
너무 is "too"
많이 can be "very" sometimes when you translate it but in Korean it's normal to use it like this, just as you could use 아주 instead.
If you think about it, even in English something that is much expensive is also very expensive
You should flag it. Flagging is the tool that helps the development team create alternative acceptable translations.
I use 'A' instead of 'The' , and it is unacceptable. Why? Sometimes I get confused between article and topic
Because they are talking about a specific meat, so you would use the in English.