The "solution" is to abstract to layers built upon the primary monetary layer. Tgis is how money scales. The base layer is settlement, The second layer is transaction liquidity, the third layer is credit. There are trustless ways to make these layers but they get increasingly complicated. Custodial is a made up term. Assets always have a custodian whether it is you or someone else is irrelevant, the bearer of an asset has control. People need to read Cryptoeconomics by Eric Voskuil and it shows.