If you go the direction of a basic Japanese single (eg. KLR, DR, XT) make sure you go with a model that is common for your region. For example the KLR here in North America is an A model, which is different from the C model which I believe was the type that was sporadically imported into parts of Europe. I rode a C model from Vlad to Mongolia, it's got a small tank and a brutally weak rear subframe so I wouldn't necessarily recommend it. The A model is much better suited, but I dont think you'll find many of those over in your area.

You mention the DR isn't that common in your area, unless you are a committed Suzuki fan, there's no need to go chasing any of these specific bike makes and models. Find what's common in your area, look at a few of the ones available and pick one that meets your needs. If you have easy access to XTs, go in that direction.

In regards to KTM, for some reason there aren't many KTM riders on this board but you will run into many, many KTMs long distance touring. They all seem pretty happy with their bikes and have figured out a way around the well known weaknesses of some models and years, so I'd keep looking at those as a very viable option.

Might exceed your budget, but prices are a lot better now and the BMW XChallenge certainly got rave reviews on the route you are thinking of riding from Colebatch.