I’ve been using OBD Fusion by OCTech, LLC
It’s more expensive than other options but in my opinion much better designed and made. The developer has also been responsive to my inquiries when I had trouble importing the custom csv file of PIDs. It doesn’t currently support custom PID equation entries but they’re working on adding that functionality. Luckily that can easily be done in the spreadsheet afterwards from the other data points.
The free options such as EngineLink LE looked and functioned like cheap garbage. But they are an option if your tolerance for software quality is higher than mine.