Is it wrong to leave Ph.D program after MS?
It is often frowned upon to leave a PhD program after you receive an MS, if this is your intention from the start, because the program would have admitted someone else who wanted a PhD had they known. However, if you don't tell anyone that this is your intention, there is no way for the program to know; PhD students drop out all the time after getting a masters (it is usually assumed that this was not their original intention). But ...

You are lucky enough to have been accepted to a fully funded masters program! If you think it is a good program, you should go there. Fully funded masters programs are quite rare in most fields. Do the right thing and allow the person who really wants a PhD to enter the PhD program. The PhD program, most likely, has offered you funding assuming you actually want a PhD.

Now if you had not been accepted to this fully funded masters program you would have had a tougher ethical question. For people not accepted to such a program the options are to (1) doing something that is morally questionable (at best) and going to the PhD program, (2) getting a job and waiting a few years until that employer funds a masters degree or (3) paying the money for a masters degree and potentially going into debt. That is a much harder question to answer, my inclination on that one is to go for option (2) if at all possible. But the fact that you were accepted to this funded masters program makes doing the right thing a much easier decision than for most people in similar situations. Take advantage of it!

Response to edits made to the question: Note that you can still evaluate whether you want to go on to a PhD from your separate fully funded MS program. After your MS, you might even get into a better PhD program and have a better idea about what PhD program/advisor would be best for your research interests. The fact that you "may" want a PhD in the future is actually a good reason to take the fully funded MS program. The opportunity costs of delaying the PhD by 1-2 years, by doing a fully funded masters is much less than the opportunity cost in delaying an industry job. .