There are many issues that might cause this behavior, a soft reset as suggested by @geirandersen may work, if not, first try it again after charging it for at least 5 minutes with the manufacturers charger and cable from a known good outlet. Try the forced reset again holding the power button until you see the poco logo appear, release the power button this will take at least 10 seconds.
If the phone does not respond it may be stuck in a boot loop [https://m.youtube.com/watch?v=xrfXqMrIp8A|this video] shows you how to disconnect and reconnect the battery which will reset the phone without losing your data.
If that fails the problem is most likely a hardware issue. If the phone works ok while charging but not on battery, the battery is probably in need of replacement.
If none of that works it needs to be repaired ; has it been exposed to any liquid spills?
Dropping this device can cause damage to among other things solder joints repair is possible but requires board level repair. There are members in the businesses section here who can help or you can search for a local provider.