All the effect checkboxes have now been set to ON by default, and are sticky (meaning that if you disable preview, on next launch of Illustrator preview will remain disabled). This functionality now is available in our latest release build – 24.1.1 for Win and 24.1 for Mac which is available worldwide now.
What’s new in 24.1: https://helpx.adobe.com/illustrator/using/whats-new.html
You can update to the latest release using Creative Cloud desktop App: https://helpx.adobe.com/in/creative-cloud/help/creative-cloud-updates.html
Thank you for all the feedback.
An error occurred while saving the commentD G commented
Can anyone offer insight into the thought of setting to off by default? What's the rationale?? Is it a difficult feature for developers to make work? Just one reason please. Something. I'll settle for anything!!