Can be anything from driver crashes to overheating. Best check the Windows Event Log first and check for warnings and errors. It’s on the Start panel if you search for “event”
reinstall your video drivers
Every major windows update or feature pack will whack your nvidia drivers
you need to reinstall them after each windows update.
an i3 is really kinda gross for ue.
I wouldn’t use less than an i7 or shaders will compile forever.