I can see exactly where the bank is coming from, You have the funds to purchase , but want the bank to take a risk on you with your investing agenda.
Your investing in property, and maybe other avenues to maximise your return, but these are funds you have, and are willing to risk it..
Your not employed, and if things go belly up with any of this, bottom line is, you don't have a job for continued income in which to service your loan.
A certain well know multi millionaire also had a very much funded deep well of money, made some bad investments/choices, and it all came crumbling down, you are no different. As far as the bank should be concerned, there would be nothing to stop you taking a punt on crypto or some other no-brainer and end up in a bad situation.
There is a risk here in what you want to achieve, having a proven ongoing employment record, would see them lay out the red carpet for you.