I’m not sure I can follow. If you “Execute” a workflow on Hub/Server you can choose between immediate execution (the default) or scheduled execution. The latter has to be set explicitly in the dialog. Therefore your second screenshot is the expected behaviour. The third screenshot shows either an execute dialog that has just been configured by you or a dialog for editing an existing schedule. The latter isn’t available through the “Execute”, though, neither in classic nor modern UI. Instead you have to “Show/Edit Schedule…”.
I wanted to check the exisiting schedule of a workflow on our server.
The only way I have found so far of getting to the scheduling dialogue in the new UI is via the ‘Execute’ option in the context menu (as in first screenshot). The ‘Display schedules and jobs’ option shows the web version which doesn’t have the same details as the dialogue.
Switching to Classic for the same scheduled workflow I use the Show/Edit schedule to see the schedule dialogue settings which were as expected (shown in the second screenshot).