Compiling UE4.23.1 from source is taking up 90GB+ and growing each time I compile!!

If you stick to one Build Configuration the size should not increase. Note that when you open the Editor for the first time it will build the DerivedDataCache which takes up another 15 GB or so.

I have built the Development and Debug configuration of the engine and it uses 115GB, 30GB of binaries, 27GB of intermediate, 20GB of plugins and 19GB of source.