Which platform is worth keeping?

I have now three accounts ETrade Fidelity Charles schwab As i will be leaving Broadcom/VMware soon(based in EU and waiting for our turn) What accounts are worth keeping? I don’t want to have small amounts on each and next company I’m joining is also using Charles Schwab Is it worth keeping all? Or should i close 2 and keep charles schwab Is it possible to move stocks or i have to sell only ? For now i only have vested RSUs on these but in future planning to invest on same to diversify my portfolio #personalfinance #investments