Hello I want let the Provider Identity my Router as Smartphone
Is this possible?
It depends.
If you have in mind mobile network (3G/LTE/5G), then no, as the provider can always check the equipment IMEI and it cannot be changed - in many countries doing so is illegal so the equipment vendors cannot sell devices that support such change.
For ISPs that use Ethernet and only authenticate client devices by their MAC addresses this is usually possible, but you may need to imitate some more characteristics of the ISP-provided hardware to get the same treatment (the ISPs are quite creative). But if the ISP normally manages the CPE routers remotely, no amount of manipulation will be enough as their management system will be unable to talk to the Mikrotik and will complain about it.
Some have speed limits and you can maybe change this:
https://help.mikrotik.com/docs/spaces/ROS/pages/30146563/LTE#LTE-Avoidingtetheringspeedthrottling