How do I fix a loose CPU

I bought this phone broken, the upper part of the aluminum frame was bent a lot. So I basically bent it back to its place, swapped front camera, sensor and the upper loudspeaker. Now I am noticing that the phone sometimes gets stuck in boot loop of sorts, and if i press the spot where CPU is, it boots up normally. Usually it works for 10-30 minutes or so, and then reboots, and starts the cycle again. So I’m thinking it’s the CPU’s fault, how can I sort this issue?

I am only a hobbyist, don’t know anything about soldering, but since the phone cost me 40€, I am willing to give it a try with something I am not experienced in.