from datetime import datetime
strdatetime = '2026-01-30 11:27:35.721'
strformat = '%Y-%m-%d %H:%M:%S'
typedatetime = datetime.strptime(strdatetime[:-4], strformat)
milliseconds = int(strdatetime[-3:])
typedatetime = typedatetime.replace(microsecond=milliseconds * 1000)
print(typedatetime)
'''
run:
2026-01-30 11:27:35.721000
'''