833-735-1895

wanted me to call a number claiming to be my bank

This is a legit number.

Well, it is "legit" in the sense that it does not violate any of the rules that determine valid phone numbers in North America.
However, if you are trying to claim that calls from this number are "legit", you need to provide more proof than what you posted.  Such as the name of this supposedly "legit" caller and a link to a verifiable website that links this number to that person or company.
Otherwise, you appear to just be another shill for some scam operation that is using or plans to use this number as part of their Not "legit" scam.

Call back got a message in Spanish then "for English press 9."  Then got,  "Welcome to the Fraud Detection Message Center.  Please enter the case number followed by the pound sign."  I did find the number listed on Boon Bank Iowa fraud alerts; https://www.boonebankiowa.com/personal/additional-services/text-fraud-alerts/
That sites says this number is for Spanish but for English call 833-735-1894.  I found a couple of other bank sites that list the 1894 number.  When I call that number I get the same recording except in English with instructions to press 9 for Spanish.   I looks like a fraud detection center for multiple banks or businesses.  However, it's always a good idea to call your bank or whatever financial institution this fraud alert references.

Now, your post is far more informative and believable than a post by someone who comes here and simply posts "This is a legit number."
As we both know, shills for scammers love to come here and post things like "It's real, it's real!" before and during a scamming call campaign.

Too true, Nimrod.  And who knows, maybe some scammer is spoofing it. Cheers. :-)