For a heavily mixed zigbee/zwave environment, it would be nice to have a single AIO repeater product that extends the range of both zigbee and z-wave.
The Lowe's Iris plugs did back in the day. I have around 30-40 of them (can't remember count) but I don't have the Zwave part linked to Hubitat since I have heard they don't play nice with others.
As indicated by @jonathanm8, the only product I’m aware of are the Iris v2 outlets (made by Centralite). However, depending on the firmware version of the outlet, they can be terrible for zwave meshes.
I use Tuya USB zigbee repeaters, and Aeotec Range Extender zwave repeaters.