Lasts like 2 days before crashing, fix

Perhaps a bad unit or config? I have one working well.

What storage are you using? If USB, what exact model of USB stick?

Lasts like 2 days before crashing, fix

First of all, you should create a ticket with support by writing an e-mail to support@mikrotik.com describing the issue, how to repeat the problem and providing Supout.rif file from the device.

Without the Supout file, it can only be a guess as pcunite said. But you should first try to Netinstall the device before proceeding with anything else.
https://wiki.mikrotik.com/wiki/Manual:Netinstall
As the wiki page says: Always try using Netinstall if you suspect that your device is not working properly.

lol