This Dropdown options render from getMetadataValues() function which is available in Magento\SalesRule\Model\Rule\Metadata\ValueProvider.php
So, You can create plugin for that because, it's public method. I created plugin for that and get output as like you want.
Follow this below steps for that :
1) Create di.xml to set plugin at app/code/RH/...
Try using "Products Subselection" for you conditions (instead of "Product attribute combination" that you are using right now).
That is, make sure that the condition of your first rule looks like this:
and the condition of your second rule looks like this: