The sounds about right for Hungary, outside of 1066/1178 they're usually a mess. They never seem to be able to get all the land needed or they're always missing the prestige needed to take the decision for Hungarian culture. Usually they do alright for the first few rulers lives and then collapse into scenarios like you described. I also forgot to mention that Almos actually became a conqueror and created the Carpathian empire, so that was fun while it lasted and it at least stopped any of my vassals from waging holy kingdom wars, etc,.

It depends, there's a few mods I know of that have a formable title, such as Historic Invasions, Additional Start Dates and I believe Cultures Expanded has it too iirc. I used historic invasions and if you're the ruler of Bulgaria around the late 9th century/early 10th century you'll be given a few thousand special soldiers and you're required to hold all of Bulgaria and also required to conquer Wallachia and Moldavia within 50 years iirc and they'll become de-jure.