Hello,
It is unfortunately not currently possible to change the defaults. (This will be easy in the upcoming release, since the JavaScript code attached to the views will be overridable.)
For now, you can go ahead and edit the file wp-content/plugins/wallets-exchange/assets/scripts/wallets-exchange.js on line 1260:
self.selectedTimeframe = ko.observable( '30m' );
It’s safe to edit this file because I don’t expect to be releasing any more exchange versions before the wallets6 release.
The chart already uses the TradingView library.
with regards