It is not 'one or the other. That is just your absolutist take on the topic.
We have been told by numerous female trans people who have taken testosterone, who understand that in doing so they will take on male cues to their face and body, that they understand that their decision to do this means that their appearance may cause other female people distress.
Your absolutist take misses a significant point. The male cues in a male body do not disappear with hormones and surgeries because it comes down to skeletal proportions and facial proportions as well as voice. Male people cannot change their gait for instance. Hair line is another factor, although some male people attempt to disguise this.
Female people taking testosterone do develop some male facial cues that can cause others distress.
Those female people who come onto FWR acknowledge their choice to take testosterone and they also tell us that they then choose to find alternative solutions to their needs rather than enter female single sex spaces. Even if they are welcomed into female single sex spaces, on account that they are female.
Of course, female people who have not taken testosterone do not have those percieved male cues.
So. No. It is not 'one or the other'. It shows you have a very simplistic understanding of the issue to state that it is 'one or the other'.