Problem with getting my heated bed to heat up

Hello everyone, I need a bit of help with properly wiring the heated bed for my cheap 3D printer from Anycubic, which originally came without a heated bed. I'm trying to retrofit a heated bed, but in a somewhat safer way using a MOSFET. Unfortunately, I can't seem to get the bed to actually heat up. The temperature sensor, which I also retrofitted and placed in the middle of the heated bed, is working perfectly. So far, the main power supply comes through DC1 using a small power adapter. [See Pic1] According to some online research, this setup should roughly work if I connect a significantly more powerful power supply instead to the connections labeled "5A" and "11A" (no longer using DC1), and connect the heated bed directly to the "Hotbed" connector. [See Pic2] I don't have such a power supply, otherwise I would try it out. However, I'd like to take the safer route anyway, using a MOSFET and a second, smaller power supply. So currently, my setup looks something like this: [See Pic3] The power supplies are, of course, strong enough and both rated for 12 volts. The heated bed was also marketed as a 12-volt version. What puzzles me a bit, though, is that mine doesn't have the circled SMT components. Those spots are just empty. [See Pic4] I'm using Marlin 2.1.2 as firmware, and I only changed the following line from 0 to 2. Do I need to change anything else somewhere? [See Pic5] As I said, the heated bed unfortunately doesn’t heat up at all, and I don’t know why. Thanks in advance for your help.