NEW Pc drastically underperforms

These are my old specs:
Fractal Define 7 PCGH EDITION
Intel i5-13600KF mit 6C+8c/20T/ 5.10GHz Turbotakt, 24MB Cache
Endorfy Navis F360
Gigabyte Z790 D DDR4
64GB (2x32GB) DDR4 Kingston 3600MHz Fury Beast
2TB Samsung PM9A1 M.2 PCIe 4.0 x4 NVME (L 7000MB/s ; S 5200MB/s)
20GB AMD RADEON RX 7900XT
850W Corsair RM850x (80+Gold)

i changed the motherboard, CPU and RAM

MSI B850
Ryzen 79800X3D
32GB (2x16GB) Crucial DDR5-6400 CL32 Pro

I reset windows. I ran a windows clean up programm and installed all the drivers.
Audio, Bluetooth, AMD Chipset, AMD adrenalin
When i play games the CPU nor GPU is maxxed out but i get only 120fps in Apex Legends.
What steps can i do to debug this?
How do i know if its a hardware or software issue?