My plastic fixing process revolved around superglue, and fiberglass, sometimes carbon fiber, both I have plenty of on hand from my other interests.
I use superglue to glue the two halves together and let it cure and treat it as ultra fragile
I can go as far as digging grooves with a dremel and cut off wheel/saw, and even farther drilling tinny holes at opposing angles within that groove.
Cut fiberglass to fit inside the groove, fill the groove with superglue, tweezers to lay the fiberglass into the superglue, then the nose of the superglue bottle to fully saturate the fiberglass. It does not go fully clear but it is obvious when it is fully saturated.
I don't stress the break for many hours, preferably overnight, and if it is still stinky the next day I let it go longer.
This process can yield repairs far stronger than the broken piece ever was
Issues can be the fiberglass sticking to the tweezers. This process does not work well with superglue gel. and some superglue brands are more prone to glass sticking to tweezers than others.
All surfaces get wiped with isopropyl alcohol first, knowing it might make black plastic white.
Black sharpie can do wonders for cosmetics.
On repairs which need to remain highly flexible I attempt to saturate fiberglass with Shoe goo/amazing goop.
On the broken part in the OP, I'd use two dabs of rtv and masking tape or double sided tape while awaiting delivery of new part and save my superglue for something else. If the part was unavailable new, Id probably use more masking tape and clear rtv rather than fixing that small tab, is its likely the other side will just break too.