Internet broad band

Depending where you will find apartment, in some areas is very difficult to have normal internet, and generally speaking infrastructure in Montenegro including coastal region is very bad. Electricity blackouts are common (also depending where you live) but they do not last long, so UPS is must to have. If you have land line in apartment (which is real exotic here) you can have ADSL internet from biggest provider, part of ex Post office, now owned by T-Com, for 25e per month and you get 5Mb/256kb of speed, unlimited download, ping also varies, mine is around 70-80ms. Last years some other providers are spreading their infrastructure for internet and they are offering some better deals.
Most important is to choose well area and apartment where you will live, and you will have normal internet and other infrastructure.

No way to have 10Mb?

T-Com offers maximum 7Mb/s for 45e which is too much, but M-KABL offers 16Mb/s download 1Mb/s upload for 39e, but I do not know how good coverage they have at the coast, beside Bar where they are spreading pretty much, in Podgorica, capitol, they are good.
But to be honest, speed is not so important, even 4Mb is enough for couple of users, pin time is much more important, especially for live stream or video calls