Hi, need expert advice

I have a Msi mpg B550 gaming plus and ryzen 5600x and 2x8gb ddr4 4000mhz cas18 dual rank memory, brand TeamGroup, model Dark z alpha. Computer was ruming fine with xmp on, 4000mhz, infinity fabric 2000mhz 1:1.
Yeaterday I brought more 2x8gb exactly the same brand and model to match the ram I have and stay with 32gb (4x8gb modules)
Issue is, with 4 ram modules the computer only boots if I disable xmp and manually decrease ram speed to 3600 mhz. Anything above it will not boot. Im not an advanced user so I only set ram speed and infinity fabric speed (in this case 1800mhz), the others Settings are all Auto.
What can I do to have 4000mhz, should I try to change to another pair and test again? Or system can't reach 4000 with 4 modules and in this case I should buy another memory 3600 buy with better latency like 16? I think makes no sense to have 4 modules that are out of the box 4000mhz cas18 and have to underclock them to 3600 cas18.
I don't have the last bios update because it's a beta but maybe I'll try to update and test.
Apreciate some advice, thanks in advance!