Hi,
Yes, it's possible to hide all orders on chart by using the related hotkey ('s' key by default). You can customize it in the settings if needed.
Indeed, the option is available in the Metatrader theme, but not under the TradingView theme.
This option will be added under the TradingView theme in the future, under the chart properties, in the upcoming "trading" tab (like under TradingView). Moreover,
you are not the first user asking for that, so we will likely add it in the next release.