Define "kind of open source". :-)

It already is partial open source. Full open source is not going to happen.

My take on this: Define how much you are willing to risk based on the level of trust that you have for a software. Only enter account secrets for accounts that have assets that matches your level of trust and accepted risk, e.g. create small asset accounts with another software and only enter secrets for these small stake accounts in my software. You could still use the "view only" functionality for your big stake accounts in my client and of course all other functions that don't require you to enter a secret.