Haha! I know exactly how that feels. My hearing is extremely bad. When I finally had to ditch my flip phone a few years ago for an Apple SE, I thought "How the hell am I going to answer the phone if it's in my pocket & I can't hear it?"
First I went to a website that had Foley sound effects for sale. I checked out fog horns & ship horns, but they weren't quite right. Then I came upon a submarine dive horn (AAAH-OOOO-GAAAH, AAAH-OOOO-GAAAH!!), which was PERFECT. Loud as hell!! I looked up online on how to convert it to ringtone format. The fun part was being out in public & when my phone rang, people would stop & look around with a "offensive initials not allowed?" (edit: What the ****) expression on their faces.
But my hearing continued to deteriorate, so I didn't always hear it. I found something called Ditto, which is a tiny device you can clip onto yourself (i.e., t-shirt) that connects to the phone via Bluetooth & vibrates when your phone rings. It worked, but it eventually quit working. I tried to order another one, but they no longer were in business.
I searched for similar items, but they all seemed to no longer be made. I don't like to traffic in conspiracy theories, but I bet Apple had a hand in this in order to promote the Apple watch, which can be set to vibrate when your iPhone rings. All these other devices needed apps on your phone, & they were no longer available in Apple's app store.
So I finally broke down, gave in & bought an Apple watch (Series 3, the cheapest one). It actually works very well. The extra benefit is with the increased shopping I do online in the last year, I have lots of deliveries, & USPS, UPS & FedEx no longer ring the doorbell when the leave something anymore (most of the time I can't hear it anyway). But since they issue tracking numbers, you can have these services send you SMS updates on the package status. When it's delivered, my watch vibrates, so I can retrieve the package immediately; often I can still see the truck driving away.
My hearing dilemma reminds me of a TV sketch with Rowan Atkinson I saw years ago: