As of February 13, 2024, Google Sheets doesn't have a built-in feature similar to
a button to "Evaluate Formula", so I could step through whatever formula I wrote and find where I messed up
Google Sheets can be extended (add more features) by installing add-ons and using Google Apps Script.
Google Sheets Add-ons
To learn about the available add-ons, lick the Extensions menu on the Google Sheets editor, then click on Get add-ons.
Tip: Click the Help > Search the menus then type
Another option is to go directly to the Google Workspace Marketplace
For example, an add-on called Formula Tracer. At first glance, it looks to me that it might add the feature you are looking for. I haven't used it. Please read the add-on listing carefully.
Tip: Software Recommendations Stack Exchange is another Stack Exchange network site focusing on software recommendations. Asking for a Google Sheets add-on recommendation might be on-topic. Before posting a question or answer, please check out their tour.
Google Apps Script