Bosch Tumble Dryer Overheating

I bought a Bosch tumble dryer 2 years ago. The appliance seller installed it with a flexible exhaust tube. Six months ago it broke and the heating element had to be replaced. The repairman said that I had to exchange the flexible tube for a fixed hard plastic tube. He said that each 90 degree bend adds 4.5 meters to the length of the tube and there are three such bends, putting the length well over the maximum allowable 7 meters. He also said the tube needed massive amounts of lint removal. I removed the lint and began using the dryer again, thinking it had worked fine for a year and a half in such condition, why wouldn't it work for another 1.5. Well, it "broke" again in three months--overheated. All I had to do was hit the reset button, of course. But now what? I called the appliance company to see if they'd do the fixed tube installation and they advised against it, saying that they had seen problems like this continue even with a hard plastic exhaust vent. They suggested that I purchase a unit with a "condenser" on the back. What do you think? Switch out the flexible for a fixed tube or buy a new machine? (By the way, the machine is in my toddler's room, if that changes your advice.) Any advice is appreciated.