Onboarding Kalshi Institutional Accounts: Liquidity & Fees

Anyone else hit significant friction setting up an institutional account with Kalshi? We're exploring integrating their markets for a specific use case, and the KYB process has been quite drawn out, more so than other regulated exchanges we've dealt with. I'm curious if this is standard for them, or if we're just hitting a particularly busy period.

More critically, once onboarded, what have people experienced regarding the depth of liquidity for less prominent event contracts, and what are the effective trading fees like for larger volume? We need reliable execution for relatively modest sums, and any insights into real-world spreads and slippage would be valuable.