Cubilux USB C to 3.5mm Adapter for Live Streaming/Recording, USB C to TRRS Microphone Splitter for Laptop, Recording Adapter with Line-in & Mic-in & 3.5 Headphone Out-Suitable for Laptop/PC

A cheap line input adapter should be fine for digitizing from tape, especially spoken word. https://a.co/d/08jUwW7l

RCA out into iPhone using this device. Cubilux USB C to 3.5mm Adapter... https://www.amazon.com/dp/B0CNCL21RR?ref=ppx_pop_mob_ap_share