Get a water resistant phone and put it into an Otterbox. I'm done. There are so many available today and Otterbox makes cases for almost all of them.
What doesn't seem to work are the no-name rugged models.
Just a few months ago my wife and I picked out new phones. We both got the Motorola G5 Plus because it was on CNET's best list and very affordable. But it's not waterproof. Just resistant.
For the case we fitted the Spigen noted at https://www.androidcentral.com/best-cases-moto-g5-plus
You can get that Beetle case if you need more.
I'm looking to buy a rugged mobile phone, but there's a lot on the market and I'm not sure what I should be looking for. I'd like to be able to use the phone at work but also for my outdoor activities. Something with some water resistance might be useful. Any advice would be much appreciated!