Welcome WantFly123,
"Bush" flying is a broad term here in Canada, though generally it means landing in places which do not have airports. This may be done of wheels, skis, or floats, with amphibious airplanes being the more versatile, with less payload. Training for a PPL-A on wheels is straight forward, and less costly than it would be in Germany. It is possible to train for a PPL on floats as well, though there are fewer places to do this. One is close to me, in Orillia, Ontario. Training on skis is only done informally on an airplane you provide with skis (you cannot rent ski planes). Skiplanes are nearly always taildraggers. they are fun, and excellent to learn on, but few training organizations have taildraggers at all, and those who do are very careful where they go.
Though you may train on floats, renting a floatplane for touring is not easy. Most providers of floatplanes are very cautious as to where they are flown. There is a lot of decision making for landing in new places. Insurance companies know this from claims to recover planes from far places, so are very restrictive for rentals. If you own the plane, you can fly where you want. Understand that within a two hour flight from Toronto, it is possible to land into a lake which would be 30km from the nearest road, so help can be difficult to get. Rental places know this, so don't allow their aircraft to go far.
Landing on water or snow requires a lot of knowledge. Conditions vary greatly, and what works one day can be impossible another day. The learning for this is more than most flying schools do, and certainly not within the scope of PPL training. I would not send a PPL friend into the "bush" other than airport to airport on wheels, unless they had at least 150 hours of dedicated training and mentored flying in those skills.
Though your situation is different, being German, my advice to a Canadian who wants to do what you want to do, is to buy a modest taildragger airplane first, then find an instructor to teach you to fly in it. Once you are licensed, most taildraggers can be converted to skis or floats, and you're free to fly where you like with the plane. This, of course requires a large up front investment, but you have free use of the plane, with no rental restrictions. When you're done with the plane, sell it, and get most, of not all of your money back out of it. Doing it this way is a big step, but in the long term the way in which you will have the most freedom, and least hourly operating cost. The northern 2/3 of Canada is inaccessible to gasoline powered airplanes, as there is no aviation gasoline availbale for purchase in the north, other than by very special $$$ arrangement. But in the southern 1/3 of Canada you will find endless opportunity for bush flying. A 3000 km trip is not a problem, and if you plan your course well, you could fly such a trip without needing a radio, nor entering controlled airspace, I have.
Canada will be about the lowest cost you will find worldwide, coupled with lots of freedom to fly where you want. The all in direct operating cost of my Cessna 150M is around $70 per hour, and the direct operating cost of my amphibious flying boat is about $110 per hour. Brampton Flight Center (near Toronto) is one example of a busy flying school, there rates are:
https://www.bramptonflightcentre.com...-rental-rates/
Note that they would not do "bush" training at all, but it gives you an idea of rental costs.
If you want to try it out, go and rent for a number of hours of training, and get a taste of fight training. If/when you are committed to flying 250 or more hours on wheels/skis/floats, buy the plane, its the only practical way, and will be the lowest cost over a large number of flying hours. There is no possibility to gain the float and ski experience in Europe as you can in Canada. There is limited ski flying in France and Switzerland, and limited float flying in Italy. Norway also offers some opportunity, but is expensive compared to Canada, and you could not take a plane and tour as you would in Canada - Norway is very restricted as to where you may land, as is Germany. I have flown to all ten Canadian provinces, all three territories (the north), Alaska, and all of the continental US, Norway, and most of Europe. All of these places are different to each other. I work in Germany several time each year. Canada and Alaska offer the greatest freedom to fly "bush" style. Some photos of flying in Canada have been posted here:
Photos of private flying
If you have more questions, feel free to ask...