In times-past, Maplin sold replaceable "drop-leads" for this sort of thing.
The wall-wart fed a 2-prong socket; there were then leads with a 2-prong plug [reversible] to connect to a range of jack-plugs to fit your desired load.
Similar things are easily found with a bit of Googlism. RS sell a power-supply with the sort of 'in-line-reversible' connector I mean - see
https://uk.rs-online.com/web/p/deskt...pplies/7263040
For simpler setups, there are loads of polarity-reversers available - as an example see
https://www.songbirdfx.com/products/...nverter-cable/