It seems they need me to verify my phone and some other info.
They might be asking you to enable 2FA to your account. If this is the case then a better alternative would be to use google authenticator.
I have been able to withdraw well over 100
BTC multiple times with no/little issues, and if your account is BitGo enabled then you should be able to validate that any crypto funds in your account are segregated from their other customer's funds (eg no fractional reserves).
There are however a few things that can cause delays in withdrawing
BTC from your bitfinex account. I have noticed that if you request one withdrawal and then request a second withdrawal prior to approving the first one (via the link you receive from them via email) then the 2nd withdrawal will take a long time to process. If you are attempting to withdraw in excess of 200
BTC in a 24 hour period, then any withdrawal that puts you over the 200
BTC limit will take a long time to be processed because they need to be approved by an admin. I am not 100% sure on this, however if for some reason there are any missing deposits in your account then any withdrawal requests will take a long time to process, possibly because the amount in your BitGo account does not match what is in your bitfinex account, after accounting for adjustments, you should be able to get the missing deposits credited to your account with a single email to support with the txid's in question.