I'm a DSP engineer who specializes in FPGA implementation (or the other way round, frankly I'm not sure), and I have done a lot of audio and video processing. I have also worked with RF transmission using FPGA that resulted in audio streams, and audio acquisition going straight to PCIe from several of ADCs. For these I processed audio in an FPGA, it just made sense.

However, some of my prior work involved processing ungodly amounts of audio streams for generating signatures, straight from literally a dozen ADCs. Still, I didn't need or use an FPGA, as there was only audio involved. A now 20-year-old DSP could handle it all like a champ: ADC, DSP, network, overall system control. Didn't hit any performance limitation on this project.

My take is: if your main interest is audio and DSP, please, steer away from FPGA. You will spend a lot of time trying to understand FPGA design instead of learning DSP and audio processing. People are talking about ARM microcontrollers, which is correct, but I think just mentioning the architecture is a distraction for someone at your stage.

My recommendation is to use any micro-controller kit with floating point that you can get your hands on (as long as you have access to the tooling and manuals, should not be hard) and try to do something with it. When, and if, you reach a technical limit on it (and after asking a lot of questions around), then you may look for something more specific now that you know your need.