How to replace phones processor and do another faster

The galaxy a14's CPU is BGA (BALL GRID ARRAY) soldered to the motherboard, replacing it is an extremely difficult microsoldering process and requires advanced techniques and specialized equipment. Removing and replacing a BGA chip is referred to as CPU reballing video guide to the basics linked.

You'll need.

• A hot air rework station
• Micro pencil soldering iron
• A decent binocular or trinocular microsoldering scope I recommend 10x mag
• Fulx, low-melt solder or 60-40 leaded solder, solder paste, and uniform solder balls of the correct size which come in (0.2mm to 0.8)
• The correct BGA stencil is a thin steel stencil that aligns with a chip's pads for reballing the chip.(you can find the onnali express by sreaching the APU CPU or phone model followed by "move board" or " CPU BGA senticl"
• The correct size reballing platform for your senticl.
• Fine tweezers and other fine hand tools
• (Optional but recommend) ultrasonic cleaner
• Years of soldering experience or a good teacher

If this hasn't scared you off, here's a video of what that repair looks like. If you really want to try such a challenge, I recommend a lot of practice on e-waste PCBs from broken or obsolete devices.