There are fairly high thresholds for filing Form 8938. It isn't linked to whether one has to file a tax return, but instead to the aggregate value of specified financial assets held outside the US.
For single persons resident outside the US, the threshold is the aggregate value of specified foreign financial assets of $200,000 or more at the end of the year or $300,000 or more at any time during the year. For single persons resident in the US, the thresholds are $50,000 and $75,000. Higher thresholds apply to those filing jointly, both for residents of the US and non-residents.
Details here: https://www.irs.gov/instructions/i8938#en_US_2020_publink100045144