Onboarding speed and platform stability with prop firms

Hey everyone, fairly new to the prop firm scene and exploring a few options. I'm curious about people's experiences with the initial onboarding process – specifically, how long does it typically take to get verified and actually start trading after passing a challenge? More importantly, has anyone run into issues with platform stability or execution speed once live? I'm not looking for specific firm names, but rather insights into common pitfalls or things to watch out for regarding the backend infrastructure. I’m thinking about the real-world impact on trade management, especially with something like $EURUSD or $BTC, where slippage or delays can eat into margins pretty quickly. Any shared experiences or advice on evaluating this aspect would be helpful.