I have been jailbreaking my iPhones starting from iOS 6 up to iOS 10. Never ever I have been stolen private data or money from my bank/creditcard/PayPal due to my jailbreaks.
As long as you stick with the trustworthy repos and tweaks/apps, you should be fine.
Do some research (checking the jailbreak subreddit is a very good start) before you install a tweak/app.
I am so glad, after years, I can customize my iPhone (11 Pro) the way I want to use it.
I mainly use jailbreak apps/tweaks that enlarge true productivity and some springboard layout tweaks.
As long as you stick with the trustworthy repos and tweaks/apps, you should be fine.
Do some research (checking the jailbreak subreddit is a very good start) before you install a tweak/app.
I am so glad, after years, I can customize my iPhone (11 Pro) the way I want to use it.
I mainly use jailbreak apps/tweaks that enlarge true productivity and some springboard layout tweaks.