Here is what I'd do if I were you:
Build a list of all the companies you could/want to work for
Build a list of all the linkedin profiles of their HR/recruiters/talents or (co)founders for small startups(you can use phantombuster or a custom puppeteer scraper)
Find all their emails using wiza, dropcontact or a similar tool
Use a mailbox warmer for a few days/weeks to prepare your mail address to send lots of mails without getting flagged as spam
BCC all of them asking if they'd be open to hiring part-time (or use lemlist)
you can also send automated linkedin invites/messages to them