Question on the close loop gain and bandwidth of this OpAmp configuration
Just think about it and draw on the voltages: -


A is the input voltage \$V_{IN}\$

B also equals \$V_{IN}\$

C is made to equal \$V_{IN}\$ due to op-amp feedback

D has to be also \$V_{IN}\$ because no current flows through \$R_1\$ hence, the gain is unity.


In effect, \$R_1\$ could be removed. And, this means the unity gain BW is 1 MHz.