Is mine is the only opinion I'm qualified to express without attributing by inference an alignment with the shared opinions of unspecified others?
Yes.
Your own opinion is the only one you are fully and directly qualified to express, without any inference that you speak for, agree with, or align with the views of unspecified others.
When you state “I think X” or “In my view, Y,” you are reporting something to which you have privileged, first-person access. No further attribution is required, and no collective endorsement is implied.
The moment the claim shifts to “we think,” “people believe,” “the consensus is,” “our side holds,” or any similar formulation that points to an undefined group, you are no longer merely reporting your own stance.
That attribution is an inference (or sometimes a projection). It requires evidence, specification of the group, or explicit qualification if you want to avoid the charge of speaking for people who have not authorized you to do so.
So the short answer is: yes—your own opinion is the only one you can express with full qualification and zero necessary inference about the shared views of people you have not identified. Everything else carries an extra layer of justification.