Yes! On my travel checklist I have "REMOVE BROKERAGE APPS FROM PHONE"

Unless you are a day trader, I do not see a reason to ever have them on your phone.

You're probably right. I rebalance my account 4 times/year. I'm thinking it may be best to have one "secure PC" that I do my balancing on, and even remove the passwords from my password manager.

for paypal, i only ever use a login through the website on the rare occasions i have to use it. for other apps like cashapp/venmo, do they even have a non-app method of using them?

For those, I would only connect them to a bank account with a relatively small amount of money in it.

you just described every single account i have =(