Hello,
Mojave (10.14.4) can run on Coffee Lake (Intel's 8th gen, 2019) CPU.
Example :
a) i5-8500, i5-8600, i5-9600K, i9-9900K ( iMac19,1 )
b) i3-8100, i5-8500, i7-8700 ( iMac19,2 )
https://dortania.github.io/OpenCore-Install-Guide/extras/smbios-support.html#how-to-decide
Do some research...