By the way, I've been with countless recruiters in the past. They haven't been very helpful.
I've been to their offices a few times, have been on many phone calls and get moved around from job opening to job opening but I never have gotten an offer because of a job recruiter.
Currently I use BuiltInChicago, Indeed, Craigslist, WeWorkRemotely, Angel.co, and LinkedIn for sending in applications.
I still need the following questions answered, as mentioned in the OP...
What are some places in the Chicago area that:
* Don't care what tech stack you've used?
* Have a large enough tech team to tolerate a greater ramp-up time for new hires?
* Years in the field mean less to them, because they can just hire and place someone where it's appropriate?