https://cfo.dc.gov/sites/default/files/dc/sites/ocfo/publica... suggests that the DC police have had a stable budget since at least 2018.
https://ibo.nyc.ny.us/RevenueSpending/nypd.html suggests that NYPD have had an increasing budget since 1980.
https://www.injusticewatch.org/data/2020/chicago-has-nearly-... suggests that Chicago PD have had an increasing budget since 1964.
Do you have some sources for the "underfunded in the past decade"?