Hello Hal and welcome!
Currently there is a new law proposal which is changing the situation, but it is not final yet, so you need to keep yourself informed in the coming weeks.
Until now it was very easy to obtain temporary residency whether you were opening a company or buying a property.
In the project of the new law, there's a potential obligation to hire 3 people including 2 montenegrin nationals which makes things a lot more complicated. However, there should be some exceptions for IT companies for example etc. Also there's the option to gain residency with a Digital Nomad Visa, which has less obligations. For residency by property ownership, there was no minimum value but now it may be revised to minimum 200k...
As I said, it's not final yet but you need to stay tuned. If you need some contact with an accounting company that helps with residency matters let me know.
Cheers!
Tsarina