Oh definitely interesting and worthwhile! (Although I haven’t yet been to Kosovo or North Macedonia).
Northern Greece, is, of course, safe to visit and just as easy to drive as Montenegro. But the busses are good and easy also. There is beautiful countryside and interesting cities and villages - more than I had time for. My report will tell you more than I could quickly - just skip to the parts that interest you.
https://community.ricksteves.com/travel-forum/trip-reports/3-weeks-in-northern-Greece .
Here is my report on my 2 week adventure in Albania. I really loved every stop. https://community.ricksteves.com/travel-forum/trip-reports/albania-a-lovely-adventure
But if I needed to hurry, Korće is a bit out of the way unless you head into North Macedonia from there. And if you aren’t a beach person, you could conceivably skip those areas, which I hear get very full in the summer. I have recently been missing Albania - it may need a repeat.
Driving in Albania - I chose not to, as a solo traveler. But tourists do. Just double check your routes ahead of time to be sure they are in good shape. Just because there’s a road locals drive, doesn’t mean a tourist should. Lol.
I flew into Tirana and started there, finishing up in Thessaloniki. I highly recommend both areas, more especially since you are experienced with Bosnia and Montenegro. Let me know if you have a question I might be able to answer. My 4 weeks doesn’t make me expert.
