Why is my motherboard heating up again and again?

I bought this phone in August 2023,and used it for almost one year . The motherboard heated and stopped working.After that I got my motherboard changed from a local store and it worked for almost 6 months and now it has stopped working again and it heats a lot when ever I try to switch it on.If there's a solution rather than getting a new motherboard from company ,then please tell me.

I will be very grateful to you .......