I am a dev in a LA based software company, in the past year of 2020 pandemic as permanent remote got popularized, I am also seeing a trend my company is hiring more and more from such agencies (Turing/Andela/Upstack/...) with developers from overseas (Brazil/Ukraine/Nigeria/...), and whenever a US based dev quit, the company can hire 3 or more devs from such oversea places, and the company has actually ceased hiring within US, even though our company's website career still shows hiring within US, but I know all recently joined ones are based overseas (via some such agencies), no new ones within US were hired for at least many months as far as I know; a dev based in such oversea countries can live well on $1k or $2k month, but a US based engineer cannot even survive; now I become the only few US based on the team, and I don't feel good about my company's future;

https://www.quora.com/Has-anyone-tried-Turing-Is-it-any-good-for-finding-gigs-What-does-the-process-look-like-after-registering-with-them

TL;DR: they are OK but they take more than 50% of your paycheck forever and give you practically zero benefits for it. It’s better to avoid them and wait for another opportunity.