I missed that. It is beyond my knowledge. It just looked like bash. If && still works as and, can you do:
setenv booti_fdt_addr ${fdt_addr_r};
if test "${board}" = "rpi" && test ${cpu} = "armv8" && test "${fdtfile}" = "broadcom/bcm2711-rpi-4-b.dtb" && test ${board_revision} = 0xC03114; then
setenv booti_fdt_addr ${fdt_addr};
fi;
But is it worth it if your nested ifs work?