You might look into using something like a regulated wall-wart or laptop supply. My dining room table (Replacing Lumiline light bulbs with LEDs) used 10 meters of strip and draws around 6 amps on high. I needed around 14 volts to overcome wiring losses and used an efficient 15V power supply adjusted down until the “bulbs” saw their rated 12V.
When driving longish pieces of strip you need to feed the “+” voltage into one end of the strip and the “-” into the other end. Otherwise the LEDs on one end will be overdriven and those on the other end will be starved for power.