Not to be an unfunny nit picker (I don’t know why I’m denying this, that kinda the whole point), but all iphones do have lossless audio streaming via AirPlay. I’m assuming that you specifically meant Bluetooth streaming, but then you should’ve said so. Furthermore, normal aptx isn’t high resolution, only aptx HD and aptx adaptive are. The phone does support aptx HD as well, but once again, you could’ve said so from the start (though 3 characters more or less might make a significant difference to most memes, this one certainly wouldn’t have had that problem)
Unless your initial recordings were lossless (they probably weren’t), recompressing the files with a lossless flag will only increase the size by a lot. Lossless video is HUGE, which is why almost no one actually records/saves it. What you’re probably looking for is visually lossless transcoding, where you do lose some data, but the difference is too small for most people to notice.
My recommendations: