Distinguishing the retroflex sounds in Urdu—recording myself isn't enough

I focus heavily on pronunciation and record myself daily to compare with native speakers, but I’m struggling to hear the difference between the dental and retroflex 't' and 'd' sounds in Urdu. I feel like I’m hitting a listening plateau where I can technically produce the sound if I think hard enough, but I can’t catch them when a native speaker is talking at normal speed. Does anyone have a specific drill for ear training?