Is It safe to remotely access my organisation system through RDWeb Access  Or VPN is required ?

Hi

We are having RDWeb Access installed on Windows 2012 server in our network.

For Staff to access the network drives and applications outside our network,  they go to their laptop browser and type  https://desktop.myorg.co.uk/RDWEB
Once they put their credentials and, on the prompt they land in on the following page.
Please see the attached snapshot.

On the second page, once they click the computer icon “My Org” – they log into the RDWebserver and once they are logged in here, staff can access their drives and application.

This type of remote access setup was done by my predecessors.

With current Covid-19 situation, staff are working from home and I have given them remote access.
Now I am bit concerned  and please let me know , if current setup is safe way to access our system from outside of our network ?

OR

Do I need setup a VPN  and then force the users to connect to VPN first and to the RDP into RDweb access server?

Please advise and any help much appreciated.

Thanks in advance.
RDWeb-access.jpg