I know this is quite a bit of reading, but I really recommend looking at
then you can maybe explain, what you want to achieve.
When you set the date using the date picker it will set the Time component to 00:00 AM of the date selected.
I.E. When using localize in time zone Amsterdam (UTC +1) this means that when you select the date 1 febr, the value is 1 febr, 00:00AM localized => stored value is UTC and thus 31 Jan 23:00
So when you set localized false => all you dates appear with -1 day.
Fix: change all your date values, which are set before changing localize; addHourse($DateTimeValue, [TimeZoneHrsOffSet])
How did you localise your dates? Did you use the localise date yes/no attribute on the domain model or did you format dates in a microflow? If you used the later and did not store your original dates it will be a tough call