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 commentNoel Sufrin commented
Everyone here is correct. Adobe, please stop sitting on your hands and fix this. You're wasting untold hours of your designers' time by failing to address this ridiculously basic need. Just because you feel like you're the only game in town, it shouldn't stop you from adding basic UX improvements that are a decade overdue. I'd much rather have this functionality than some flashy new feature I'll never use in a lifetime.
Thanks for listening ;)