Friis transmission equation (log scale calculation)
Why is G in log scale in dBi ? I thought that dBi is in log scale dB


In case you didn't know dBi means the gain of a real antenna compared to the gain of the theoretical but useful isotropic antenna. So when the formula says this: -

$$G_{RX,dBi}$$

It refers to the gain of the actual receive antenna compared to the gain of an isotropic antenna and expressed in decibels.


  La in dB, in log scale is it also in dB?


No, \$L_a\$ is a real number because it is converted to a decibel value by your main equation that you wrote.