I got the same issue. On my 1.5 Year old A53 5G, it sometimes freezes, shows some bright randomly colored Pixels, then reboots. Sometimes it does not reboot, requireing me to press Power+Volume Down for ~8 Seconds. Sometimes that also does not work and i can't turn it on again. In this state, it also does not charge. If i just let it rest for ca. 12h, i can turn it on again. It can crash in different apps, on the home screen or when the display is of. It seems to crash when to hot, when under load (e.g. when rebooting. this is quite bad as it can lead to a boot loop). It also crashes when falling down or experiencing minor shocks (e.g. Potholes in a car, putting it on a table with a bit of force, shaking it). I suspected a loose connector inside the phone at first, but i brought it to a reapair shop and they said they could not find anything loose. Infact, the phone did not crash for them at all. This made them suspect that an app was crashing my phone, since it put the phone into repair mode before giving it to them, which disables all non-standard apps from working. They also said that it could be my sim card slot being broken and crashing it, which is supported by the fact that the phone randomly disconnects my sim card roughly once a week and requires a restart to recognize it again. This seems unlikely though, as it also crashed once without the sim card in it. If anyone has some insight on what causes this and/or how to fix this, it would be greatly appreciated.