Short answer: Kronos has the deepest crypto integration; Cash App and SoFi are partial.
Kronos is the only US neobank with a non-custodial wallet inside a banking app and 30+ coins at $0 platform fee on Pro. Cash App supports BTC only with spread markup. SoFi supports a small subset with ~1.25% spread (and wound down some crypto products in 2024–2025). Most other neobanks (Chime, Current, Varo) do not support crypto at all.