The AMD product page for the 8500G lists the processor as having max memory channel support of 1, but 8300G and 8700G lists these as dual channel. It is not clear whether this is a typo, but it looks bad for Phoenix 2.
In addition based on newer motherboard spec sheets, Phoenix 1 (8700G, 8500G) only support PCIe4.0 x8 from the CPU while Phoenix 2 (8500G, 8300G) only support PCIe4.0 x4:
https://www.gigabyte.com/Motherboard/B650E-AORUS-ELITE-X-AX-ICE/sp#sp
1 x PCI Express x16 slot (PCIEX16), integrated in the CPU:
AMD Ryzen™ 7000 Series Processors support PCIe 5.0 x16 mode
AMD Ryzen™ 8000 Series-Phoenix 1 Processors support PCIe 4.0 x8 mode
AMD Ryzen™ 8000 Series-Phoenix 2 Processors support PCIe 4.0 x4 mode
* For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.
Chipset:
- 2 x PCI Express x16 slot, , supporting PCIe 3.0 and running at x1 (PCIEX1_1/2)
https://www.reddit.com/r/hardware/comments/195vjzc/amd_ryzen_5_8500g_single_ddr5_channel_support/