I'm sorry for the inconvenience of new lists user experience to you. Until now, there is no option to return back to previous lists user experience.
Meanwhile, thank you for your feedback and suggestion. We appreciate your input, and we are always looking for ways to improve SharePoint.
To more conveniently switch between the new and old lists user experience, I recommend you open a service request with Microsoft or give suggestion in the feedback portal. Many features of current products are designed and upgraded based on customers’ feedback. With requirements like this increase, the problem may well be released in the future.
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