Submit the same paper to several journals/conferences (N.B.: This isn't a duplicate of Submitting the same research to multiple conferences, though the question is related.)

I've written a paper and am looking for journals or conferences where I could present it. I intend to send the same work (with only minor changes to fit length restrictions, etc.) to several journals or conferences organizers, at the same time. The goal is not to actually publish the same work in several journals or talk about it in several conferences, but to do that in a single journal or conference, as quickly as possible. I have two things in mind:


The review process is typically very long. If my paper is rejected by a group of reviewers, I'll lose several months during which I could have found other prospects. This is made worse by the fact that calls for papers tend to occur at about the same time.
For conferences, I can't know in advance whether my institution will accept to cover the costs. If I'm accepted to a conference and my institution refuses to cover the costs, I'll have to wait for a new opportunity, which might itself become void, and so on.


Is it ethical to submit the same paper to several journals or conferences at the same time, provided that, if my paper is accepted by several publishers/organizers, I follow up with only one of them, and disengage from the others?

And, if this is possible, how exactly ? (Should I explicitly inform the publisher or the organiser of the conference that I'm submitting the same work somewhere else ? Should I tell them where exactly I'm submitting the paper ? Should I tell them after the fact if I find a new opportunity in the meantime ? etc.)
No. Simultaneous submission is rarely considered acceptable.

Each journal or conference will have a simultaneous submission policy (a.k.a. dual submission policy) that you can look up. Make sure you read it and, if you can’t find it, ask. With a handful of exceptions (e.g., law reviews), they all prohibit simultaneous submission. If you ignore this policy, it is considered academic misconduct and could get you in trouble. And the chance of getting caught is very high.

I understand your frustration with the duration and uncertainty of the review process. However, if everyone started doing simultaneous submissions, the system would get even more clogged up. The bottleneck is a shortage of reviewer time and simultaneous submissions only consume more reviewer time. Simultaneous submission is viewed as a means of cheating the system that is unfair to those who follow the proper policy.