For a design for a simple low cost power meter see;
Power meters coming soon! 2.4ghz 200W DATV and narrowband
Power meters for 2.4GHz 200W DATV or CW coming soon
I often have pallets and PCB's available for conversion or even already converted ones
Modifications to Nokia PA PCB with 2 x BLF7G22L-130N for 2.4GHz
https://groups.io/g/DATVPA/files/Modifications%20to%20Nokia%20PA%20PCB%20with%202%20x%20BLF7G22L%20G7NTG.docx
Modifications to board from Bison Electronics with three x BLF8G22LS-160BV Transistors
https://groups.io/g/DATVPA/files/Modifications%20to%20board%20from%20Bison%20Electronics%20with%20three%20x%20BLF8G22LS.docx