I did find a teardown of a TP-Link router for the Chinese market which uses it https://www-acwifi-net.translate.goog/25800.html?_x_tr_sl=zh-CN&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=sc and in this case has external ethernet PHY to support 2.5Gbps interfaces.
It appears that the SoC has inbuilt gigabit ethernet PHY as the connections in the hEX are to the ethernet ports via the usual transformers, but no PHY chips. There are some pictures of the PCB on a distributors website https://www.roc-noc.com/mikrotik/routerboard/E50UG.html
It isn’t a new SoC, originally produced by EcoNet before they merged with Airoha in 2021. The CPU is a dual-core Cortex A53.