My general advice to new folks entering the workforce for the first time is that they remember "the company" (especially big public cooperations) does not care about them. The company's only real priority is to provide value to its shareholders and the best case scenario for employees is that management sees an alignment between treating employees well and increasing the stock price. As such, the company does not deserve any more from you than you are contractually obligated to provide.

That being said, for many roles a lack of notice for your resignation is going to have the most significant negative impact on your immediate team, manager, and coworkers. HR and the CTO will not care, but the engineers you have been sitting next to for the last few years could be put in a tight spot.