Why do you think t doesn't do well with supports? I use them whenever I think I need them. As a matter of fact, I make sure I use them to keep my bridging small.

As to a heated bed, you're using BuildTak. That stuff is like superglue to PETG. I doubt you even need heat. I use glass. With a 80° bed, PETG sticks great. That bed drops below 50° (or a little lower) and PETG comes right off. So, to answer your question on the heated bed time, it depends on your bed.

You don't need a cover on your printer unless you are printing ABS, which I haven't used in forever since we absolutely hate the smell (not to mention that it tends to warp and thus needs extra extra care).