In , R&D spake
thusly:

I set to refresh/re-query the data every 10 minutes (or
similar). The problem is that when the refresh time comes it
takes some time and whole spreadsheet is out of action. User can
not do anything but wait. I would expect that getting external
data should run as a background activity [. . . .]

Go to Data / Import External Data / External Data Range
Properties and tick the checkbox "Enable background refresh."

=dman=