2-3 years at TSC, even 4.
NBC does not show its processing time as you can look. Could be less than TSC, but could be more. But even when it shows, the processing time is not reliable.
I got a friend applied I-485 asylum based in at TSC in 2019. When he applied, the maximum processing time is 23 months, which means he should receive his GC by now. But the processing time kept increasing.
Whenever his case approaches the maximum processing time, USCIS increase it on their website, so whenever he contacts USCIS, he was told his case is still within processing time. Now the maximum processing time is 42 months. But who's gonna know it will increase again in the future.