Had you installed any device handlers previously? The ability to add new ones has been discontinued. IDE in the process of being shutdown by the end of this year. At this point, you want to use Edge Drivers.
At this point, since the IDE, Groovy and Device Handlers are deprecated as of 10/15 and will be fully removed by 12/31, the only reason to access the Device Handler menu would be to remove a Device Handler, or edit one. You can no longer add new ones.
If you’re seeing that you don’t have any, my guess is that you don’t have any custom handlers (stock handlers do not appear there). That’s a good thing - you don’t want to be using them anymore.
Refer to Edge Drivers for the future of this type of thing.