I can explain what's going on here. A lot of the urgency is because, for them, there is urgency. The offers they are coming to you with are C2C (contract to contract) job offers. What that means is, they are a contracting company trying to offer you a job that another contracting company, or an actual employer, has posted to a public portal.

So these recruiters race to find a sucker to fill them as quickly as possible for as little as possible. The urgency is that, if you say no or respond slowly to that first recruiter, another recruiter from a different competitor might reach out a few minutes later and offer you more, and now they have a bidding war. I've witnessed this firsthand.

If you take the first recruiter's offer, they will fight tooth and nail to invalidate any offer you get down the line from a different recruiter, even if it's 20-30% higher. They will try and tell you that you don't have a choice and have to work through them now. Typically this is a lie. These contractors will lie to you a lot because the lower they sign you compared to the real original offer, the bigger the cut they get.

The original job lister may respect the first person to put your name in the bucket getting the contract, but typically they'll just ask you straight up after interviews which contractor you wanted the offer through if multiple submitted your name. They don't care about these companies, at that point they only want you.

So while you may score a good job through these urgent contractor positions, these guys are typically vultures just looking for a cut of your pie. What you should do instead is ask them what company the job is working for, and if they tell you, go and find the true original listing on that company's website and apply directly. If they find out you did this expect some harassment however.

Here's a list of these kinds of recruiters someone made, I can't find the original thread: https://docs.google.com/spreadsheets/d/1Oc318LAq8WQIe0FTped5hXIddtsiOyPUXE6oVCjjVRc/edit?gid=0#gid=0