Unfortunately that test - or at least the report of it - is of no use without a mention of the frequencies that were used for the 5G transmissions. Were they in the new band 3.6 to 3.8GHz* which is of concern due to being nearer to the aeronautical allocation, or in the lower cellular bands e.g. 2.6GHz?
It is the potential conflict from nearly adjacent frequencies that is critical. 5G cellular in the lower bands, which has been in use for some time, poses no risk to airborne operations.
* individual national allocations may be different.