I got this TP-Link AC750 Wireless Portable Nano Travel Router - WiFi Bridge/Range Extender/Access Point/Client Modes, Mobile in Pocket(TL-WR902AC)

I use it in a way like this

Wifi network(from a LTE modem ) -> This router -> Connect multiple devices to this router.

The problem is that while the devices connected to this router can talk to internet, they are unable to talk to each other. When I connect both my PCs to my home wifi network, I can simply use remote desktop.

However when I do the above config, the devices cannot talk to each other.

If I switch the router to ETH mode, then I lose internet (obviously since there is no ethernet cable), but the 2 PCs can talk to each other.

Is there a way to have communication between multiple devices even in wifi sharing/hotspot sharing mode?