I’m not certain how the WiFi modules work from the shop. I expect you can set the target IP address for emoncms and it passes data via HTTP or MQTT. If so, then yes, this means you do not need an emonbase/emonpi with an RFM receiver.
I am working on an ESPHome component to do this, but it has stalled on my lack of C++ skills. The MQTT output works fine but I want to get the HTTP interface working as well (ESPHome Component for EmonTX (ESPx & PiPicoW)).
Where is the emonbase? You can always connect it to the TX4 via the USB especially if you do not have any other OEM kit talking via RFM.
I run emoncms on a PVE LXC. Just in the process of updating it to a new container. If you use PVE then these are really useful Proxmox VE Helper-Scripts | Scripts for Streamlining Your Homelab with Proxmox VE.