Empty screen, since mobile is not supported on a reason

there!

We have a situation where we develop a very complex data platform and we don't support mobile version of the web app on a reason. Nevertheless, we have a native mobile app that supports most of our functionalities.

The main issue is we had to disable the login on our website, in order to avoid users landing on a broken page, but there are several ways they can achieve it and it is a problem. So my idea is to bring it back, but suggest an empty screen that proposes whether to use a desktop device for the best experience and/or downloading our app since I don't want to lose valuable mobile leads.

Is there a better approach that you can suggest or what can be the risks implementing this kind of solution. I am not fully confident about that at the moment and still researching.