Your LED strip has one resistor per 3 LEDs, which is the standard for a 12V strip. Each group of 3 LEDs is wired in series, with the resistor setting the appropriate current. All groups of 3 LEDs plus resistors are then wired in parallel.
White LEDs take about 3-3.6V each, so 3 in series mean 9-10.8V, with the resistor taking the rest of the voltage up to 12V.
For a strip, the resistors set the current, so you don't need a constant current driver. You need a standard 12V constant voltage power supply.
3528 LEDs should run at about 20mA each, but remember they are wired in series in groups of 3, so each group of 3 LEDs will use 20mA on your 12V supply. So, 18 LEDs/foot means 120mA/foot, so 1.3 Amps total or 16 Watts.
If you don't fancy getting electrocuted, an enclosed power supply is better than an open frame or naked PCB. I like Meanwell so I'll shill for it. They also make IP68 waterproof models.
If you have a 12V DC wall wart lying around somewhere, that can also work well.
Am I right that the adapter caused the flickering and the noise or it could be the LEDs?
If a group of 3 LEDs fail on the strip, perhaps one LED is dead in that group, or a solder joint cracked.
If one half of the strip fails but the rest works, then the copper trace which carries 12V is broken somewhere around the transition between "works" and "doesn't work."
If all the LEDs are off, or all blinking, then it's either the power supply, wires, or connection between wires and strip.
(My previous experience with LEDs is that if they failed, all of them fail)
If they are all wired in series like in some lightbulbs then yes, one single LED failing open will open the whole circuit, but this is not how strips are wired.