I learned basic accounting at a community college-- Financial Accounting (3 hr course) & Managerial Accounting (3 hr course). I later took Intermediate Accounting 1 which was also super insightful.
But those first two... Wow. They really opened up the "black box" of internal financial operations within a business, to me. Prior to those first two courses, I had no idea what happens when I pay a cashier a dollar, and how that dollar flows through a company to pay their vendors & employees (as well as taxes).
Intermediate Accounting 1 & 2 (dropped out of 2) taught me more about how accounting statements relate to the stock market & financiers.
If you'd like a free intro, you can check out this free online college-level textbook on accounting: https://www.principlesofaccounting.com/ [1]
Accounting knowledge + Digital Marketing experience has been invaluable to me as a Software Engineering consultant (in the digital marketing & small + medium sized business space)-- I understand the language of business and can predict what a customer needs much better than I could before.
[1] About the author: Larry M. Walther is Professor Emeritus from Utah State University. He previously served as the EY Professor, Head of the School of Accountancy, and Senior Associate Dean of the Jon M. Huntsman School of Business. Dr. Walther has authored numerous accounting textbooks and articles, and has served as director and/or consultant to a number of public and nonpublic companies. Dr. Walther earned his Ph.D. in accounting from Oklahoma State University and has public accounting experience with the audit firm of Ernst & Young.