Definitely, the Bluetooth speaker route is the way to go, provided it is not also a mic-related problem. As I said earlier, an iPad may well not have better sound than an iPhone. If you could try an iPad Pro and ordinary iPad, in a shop, or borrow one, then at least you might get an idea. The results I get though from comparing an iPad 5, iPad 6 and iPad Pro v1 with an iPhone SE are not that encouraging. The improved sound is one of the reasons why I got an iPad Pro.