Cybercriminals will stop at nothing to try and take control of smart devices, discover your home IP address and track your online shopping habits to get hold of bank or debit or credit card details. Fortunately, there are procedures and tools available to make their work impossible or near as impossible as, er, possible.
The first thing is to make sure you download apps from reputable sources to ensure that these are malware-free. Even so, some apps are still getting under the radar on the Google Play store, but this does greatly reduce the risk.
Second, never, ever use smartphones on a public wi-fi link at hotels, cafes etc without two very important tools.
The first of these is a VPN (Virtual Private Network). VPNs encrypt the data flow between your phone and its destination. It is important that you use a paid-for service. The only free VPNs I would use are from ProtonVPN and Tunnelbear. These are secure but the downside is limited data usage and your data is run through slow servers. My VPN of choice is Surfshark and you can read why here.
Second, you need malware/anti-virus protection. Most smart devices come with a built-in service, but these are, at best, limited in the scope of what they look for. I have used Kaspersky Internet Suite for many years, beaten only by Bitdefender is online testing. But it is a small lead.
My Kaspersky subscription covers five devices, so covers my desktop PC, plus smartphone and tablet. If your mobile device is stolen, you can detect its physical position and also wipe the device clean so your valuable data is not available.
The next tool, as essential for mobile devices as a desktop machine, is a password manager. If you consider how many websites and services you log into on a regular basis, not using one is negligent. My password manager of choice is 1Password which not only stores encrypted login details but has secure areas for bank details, credit card information, passports etc.
These are the very basic services and apps you need to protect not only your online life, but bank and other sensitive personal data.