Where do I make a feature request? Quicken for Mac

The best place for that is over in the Product Ideas for Mac Classic section. There's a specific subforum for ideas related to accounts & transactions, I'd probably start there. It would be a good idea to at least scan through the existing posts to make sure you're not duplicating one.

https://community.quicken.com/categories/manage-accounts-and-transactions-

If you do see something that you want implemented, make sure to vote for it by clicking on the up arrow in the vote box below the first post in the thread. Ideas have to get a certain number of votes before they are sent on to the developers for consideration.