What is cold/split wallet ? care to share ? I knew there is just cold wallet !!!
for me, it's use multi-wallet files for a big amount of bitcoin ... like 5 files wallets from bitcoin-core that they hold 2 BTC each.
you can loose 1 files ... but 5 files, no.
and if you store on USB key with date of folder, you have multiple record randomly area on it.
at the end, you have 100-200 files ... writed on different location ... with the same result = 5 files usable with 2 BTC on it.
and, at the end, use multiple USB key to do this.
it's nearly IMPOSSIBLE to loose a file with this strategy ... even if you loose PC, burn a part of your location or trash some clothes.
early adopter of bitcoin is a good story of loosing coins ...