Unhelpful and Overoptimistic PhD Supervisor I am currently in an unbeneficial situation with my PhD supervisor/advisor. At the beginning of my PhD, I've targeted non-top but reasonable venues for my papers and quickly succeeded with 3 publications. Since then, my supervisor has encouraged me to target top-10 Computer Science conferences or h-index &gt; 100 journals for further papers. I've submitted 3 papers to such venues and have received 2 rejections and 1 major revision, which is not great, but better than 3 rejections.
In our regular meetings, my supervisor and I used to discuss the content of my papers. However, every since I started targeting top venues and trying to do research at the required level, my supervisor was clearly not able to follow/understand my work. This went so far that, now, during our regular meetings, 95% our time is spent by me (unavailingly) trying to explain my work to my supervisor.
I don't expect my supervisor to understand my papers as good as I do, yet in my opinion there should at least be a certain minimum understanding. After all the reviewers at the top venues seemed to understand the paper quite well and gave me accurate feedback.
Regardless, my supervisor keeps pushing me to submit at top venues and over-optimistically states that my work will be accepted there. However, I typically know where my paper's flaws are, and I receive no help there from my supervisor. After submission, the (meta)-reviews stated precisely these flaws as main reason for rejection.
How do I get more qualified feedback on future manuscripts before submission? Changing supervisor is not really an option, since they are my employer and since my PhD is anyway soon complete.
Is your supervisor overly optimistic? At least not obviously so. Getting a major revision and two rejections is a 1/3 success rate. That is actually pretty good for a round of first submissions, especially to top venues. But in the end it's of course your choice where you submit your work, and if you don't plan on staying in academia, you may wish to be more pragmatic.
Is your supervisor unhelpful? At least not less helpful than other supervisors of advanced PhD students. It's not uncommon for PhD students to eventually surpass their supervisors with respect to their research topic. At some point, you become the foremost expert on your specialization. All your supervisor can then do is offer hands-off guidance and mentoring, which they seem to be doing by evaluating your papers on an abstract level and suggesting suitable venues.
How can you get better substantive feedback? I understand you also need substantive feedback that goes beyond soft guidance. Here are some sources:

Submit early and often to respected journals to get feedback by reviewers. Reviewers are selected based on their specialization, so the feedback will be more specific than what you seem to get from your supervisor. (You're already tapping this source, good.)
Attend specialist workshops and conferences (especially if, like me, you're in a &quot;journal field&quot; where conferences are largely for work-in-progress).
Approach selected specialists and ask them for feedback on one of your drafts. The worst that can happen is that they ignore you, but many people are surprisingly generous, and specialists are often interested in what people in their subfield are working on. As incentive, you could also offer to reciprocate. (Even if you feel you're not senior enough to offer them advice, there's often something you can do - be a discussant in a panel, read a draft for overall consistency etc.) And who knows - this might even lead to a cooperation.
Share drafts with other students on your own level. Even if they don't have the specific expertise you are looking for, their feedback can improve your paper, and their misunderstandings can improve the clarity of your exposition (and thinking).
Finally, you might also consider looking for a more specialist co-supervisor. I know of some graduate programs that even require a second supervisor that can be selected at a later time.