Always go direct to the official source for any update or install, third-party links are where most security problems actually start. The habit of checking the URL before downloading anything takes about three seconds and removes most of the risk entirely.
Bet with Moors is the one I use and accessing it directly through the mobile browser has been straightforward and secure. Keeping the phone updated and not sharing login details covers most of the security side without anything complicated. Betting on mobile works fine when the basics are covered and the platform is a reliable one