Should I change the format of preprint before publishing it as a working paper? I submit a paper to a journal which allows to publish the preprint as a working paper. After submission, I thought I can just take the version I just submitted and publish it on ResearchGate. But then I thought that it might be problematic to use the same format I used for submission, since then everyone knows to what journal I submitted (or at least, to what publisher). Then, if my paper gets rejected, everyone knows that.

Is this an important consideration? Is it important to change the format of the paper before putting it in a preprint archive?
Personally, I wouldn't bother changing the format.  As a wise colleague once told me, if you aren't getting some papers rejected, you aren't submitting to good enough venues.  If you're proud of the work, there's no need to try to obfuscate where it's been submitted.