You're right, but we've got a ridiculous amount of words for conjunctions too:

1. because, as, since, due to
2. thus, therefore, consequently, as a result, so
3. but, although, however, whereas, nevertheless, nonetheless
4. and, in addition, also, as well, what's more, moreover, furthermore

And these are just grouped into four approximate types, there are many more. At least these ones we're learning now don't (so far) take different grammatical forms as ours tend to. :)

But that's already one of the accepted solutions :)

Mostly... generally, if it introduces another clause, there should be a comma. I myself am not great with those, and sometimes we just need to check on the Internet.

"dlatego, że" could be used. "dlatego" on its own is more like "therefore".