There are so many ways one could work around this (apparent) limitation. Liberty software, unbound software, modifiable software. Go all in on libre rather than putting it in an awkward 'free/libre' combo - languages borrow words from each other all the time. Swap the order round and talk about software freedom, or digital freedom. Make a portmanteau like libreware...
I'm not especially good at this, and obviously 'free software' has the benefit of a few decades history among the people who actually know it. But almost anything seems better than a phrase which has a very obvious meaning that's not the one you meant, and the consequent need for fussy little explanations. Especially when most Free Software is also free software.
Alas this is something many have been debating for decades at this point. Unfortunately, there isn't a really clear answer. Both sides have good and bad points.
I'm not especially good at this, and obviously 'free software' has the benefit of a few decades history among the people who actually know it. But almost anything seems better than a phrase which has a very obvious meaning that's not the one you meant, and the consequent need for fussy little explanations. Especially when most Free Software is also free software.