Missing Supports

[Travis7s 25]

Looking for help with this in Cura 4.5 (although it doesn't seem to work in any version) This model has a small cutout in the very bottom that is about 0.75mm tall. It needs support as it droops too much when printing. Is there some kind of setting I'm using wrong or a way to force this? I tried playing around with the Custom Support plugin but that also gave me weird results like essentially building a raft under the entire model.