Converting string column to datetime column in QGIS

I have an attribute column that has a string datetime and I want to convert that to a date column. I first attempted to simply add the time column in an expression, and I only got the year/month/date, but I wanted the time as well. So I first converted it the string to a new column with format_date(), to clean up the format, and then I went ahead and used to_datetime() to convert the string into the date column. It shows up fine in the Expression dialogue but then doesn’t add the hour/minute/seconds.

What am I overlooking?

Using
QGIS version
3.16.1-Hannover
on Windows