You can answer this question by looking at the existing service.
Are the trains crowded, unreliable, and/or running over capacity? In that case it would be better to spend the extra money on upgrading the service. Or is the service good but not enough people are using it? In that case it may be better to use the money to reduce ticket prices.
Whatever gets more people to ride the trains is going to be the best solution.
> The MTA said money from congestion pricing makes up more than 50% of funding for the agency’s capital program
Presumably, those specific things can now get back underway:
> Projects that rely on the funding include modern signaling on the A train to Far Rockaway, more ADA-accessible stations and phase two of the Second Avenue subway.
[0] https://ny1.com/nyc/all-boroughs/transit/2024/02/16/mta-halt...
But that's meaningless; since capital funding from the congestion pricing lockbox will just displace debt issuance, so it's effectively just taking pressure off the operating budget, which is where the current federal funding is going.
https://www.nytimes.com/2023/10/25/nyregion/mta-congestion-p...