@Anonymous
Sorry for my very late answer, didn't saw your answer/files.
I checked the issue today
1. If all settings for units on SW side is set to feet/inch, it is unusual that Autodesk use METER as unit for that model.
But this problem was also present in older versions, like 2019.
(Just tested in 2019 because the SW files are not supported in 2018 or older.)
2. You're right, since 2020 the import works really a different way.
The created block is still set to meter, but with the right size(in meter).
Since 2020 Acad uses a sysvar to scale the block reference.
For usual this variable is for import process of other files and blocks with unit setting "unitless".
But a SW file is not a DWG, not a Block, and the created block is not unitless.
So it is unusual for the first look,
and it isn't working this way in 2019.
The variable i am talk about is INSUNITSDEFSOURCE.
Please try it confirm(or not) my statement.
Take a look to the Help[F1] if not familiar with insunitsdefsource (/insunitsdeftarget).
It is a system setting, not file dependent.
Set InsunitsDefSource to 1
Also available in your options
https://help.autodesk.com/view/ACD/2021/ENU/?guid=GUID-2E780292-7D34-4A34-8CCC-82363D4F9092
Import SW sample from above.
If i am right, the result should be
Block with unit meter,
Blockreference XYZ Skaling 1,1,1
Hoping that i checked it correct,
feedback welcome.