No offense, but 30k miles in your frequent flyer accounts (accumulated over >1 year?) is not nothing, but also does not necessarily suggest "a lot" of flying.
In Europe, a lot of point-to-point travel is now done on low cost airlines (WizzAir has a presence in Bulgaria).
As much as I hate travelling on airlines like WizzAir; the price difference between low cost and legacy carriers in Europe is so large now that it does not make sense for most people I know to tailor their intra-European travel plans on their frequent flyer program membership (and vice versa).
If you know you will be flying KLM twice a month anyway, join Skyteam. If you will be flying Lufthansa that often, join *A. Otherwise just buy the cheapest ticket you can find and use the Euros saved to buy a day access card for an airport lounge once in a while.