Improving Range for Sonoff RF WiFi + RF433Mhz Remote Control?

Hello,
I have been using several Sonoff Smart Switch RF+WiFi switches for some time now using WiFi only. It occurred to me that I needed to use the possibility of operating this switch via remote control. The test went well in terms of pairing and controlling the switch, but the problem is the very short range of the remote control even in an open area, and if there is even a thin wall in the way of the signal, it does not work. Is there any way to improve this? Maybe some kind of antenna for the switch? I hope there is a solution; I have found advice on the web for improving WiFi connectivity by attaching an antenna (wire) to the connector board, but no analogous solution for the 433MHz remote control.
Thank you in advance for your help.

I'd start by taking the remote apart and see how it's resolved, maybe the PCB antenna is weak, I have a couple of 433 remotes and the ones without an antenna only work at 20m when there's no curtain, at most a window on the way, but the receiver obviously has an antenna of the right length. The ones with telescopic antennas reach through the ceiling and about 2 walls.