If you sync your Samsung calendar with the google calendar, all the entries should show up on Google Calendar.
Hope you still have your Samsung phone. Open Samsung Calendar on your Samsung phone. Click on the hamburger menu at top left and then the settings cog wheel on top right. Click on Manage calendars under more settings. Turn on the toggle for the entry which shows your Samsung account. Back out all the way to the calendar.
You can manually sync by clicking on the hamburger menu, scrolling all the way down and selecting Sync now at the bottom.
