The TX592RDS and TX492RDS were contemporary Yamaha tuners to your AV preamp. Both are digital tuners and wouldn't be desirable from a performance perspective. If you can find one it wouldn't be too pricey.
The best tuners that Yamaha made were the CT7000 and CT1010 analog tuners. Neither will be cheap. They won't match cosmetically to the DSP-A1. I recently sold a CT7000 for $1025.
You can bypass using an over the air tuner completely by getting a Sonos Port, Denon HeosLink, or Blusound Node2i. Those will stream not only your local stations but thousands of stations from all over the planet for free. Sound quality is likely to be better as well. Most FM transmitters are configured to reach as far as possible not to sound great.
You can...