Not able to add users to a data source as Admin

Sorry to say it but, it works on my machine 🤔

What I checked is the following:

Figure 1

When I see my localhost server with the Personal mode gateway I see the same as you, no option to share (Figure 1).

Figure 2

Then when I chose the standard gateway I see the option to share, no problem (Figure 2).

Figure 3

I checked my standard gateway and its status is online and I'm an admin (Figure 3).

Figure 4

My standard gateway is online and all good to go (Figure 4).

Figure 5

And lastly as final resource I checked that in the workspace I'm an admin also (Figure 5).