Precedence issues when dealing with units is unavoidable, I think. The units program on Linux/Unix has similar issues, and they write their own parser and choose their own precedence.

https://www.gnu.org/software/units/manual/html_node/Operators.html

As Eric says, we can't change the precedence of the @ operator easily, if at all. It would likely require at least one full release (3.8) with a warning, or a future import, and frankly if the numpy community is against it you'll have zero chance of it happening. (On the other hand, if they're in favour of it, you'll have a good chance.)

If you still want to pursue this idea further, please take the idea to the numpy and/or Python-Ideas mailing lists for further discussion:

https://www.scipy.org/scipylib/mailing-lists.html

https://mail.python.org/mailman/listinfo/python-ideas

but for now I'm going to set the issue to pending.