NICs SPEED CHANGED AFTER FORMATTED

I have server works on win server 2012r with 4 NIC..
NIC0 = 10G speed
NIC1 = 10G speed
NIC2 = 1G speed
NIC3 = 1G speed
 when i formatted the server with HYPER-V SERVER 2019 .. All NICs are coming with same speed 1G WHY??
If that is normall with hyper-v server then what's about WINDOWS SERVER CORE 2019??

NOTE..

I DON'T TOUCH ANY UNDER INFRASTRUCTURE HARDWARE OR CABLE