I would separate the parts it even more.

the reason if it fails you are not messing everything.

Always used stl files no problems.
both Prusa slicer and orca slicer are good.

the one advice I would give if you want to print allot get 2 identical printers.
I went thru hell with only 1 printer and break just when I need it lol...by the time I get the part and if it is the correct one ...weeks gone by.

Now I have 2 new ones and one went bad already but at least I can continue. I want one more and I am good.