Have you tried a white noise machine? Maybe it’s not necessarily your phone or podcasts that you need but maybe a sound for yourself to focus on to doze off to?There’s a range of them ones on Amazon that have a variety of sounds and volumes. Theres also ones that don’t emit harmful frequencies (or at least I think?) like the one i have (links from Amazon below):

Bestand White Noise Machine New Generation Real Fan Sleeping Sound Machine with Intelligent Mode, Timer and LED Display for Noise Cancelling Sleep Therapy Office Privacy Travel Adults Baby https://smile.amazon.com/dp/B08GBYMBPZ/ref=cm_sw_r_cp_api_glt_fabc_7TDYK2PXX1K1T6H9Z292?_encoding=UTF8&psc=1

There’s a fan that runs inside of it that emits the noise rather than a “playback sounds”. honestly really, Hope that possibly helps!