This would simply spawn organizations the accept your money in order to purchase assets for liquidity. This would introduce frictions into the system for no benefit that I can see.

Lets push your system to an extreme just so we can see what it is obscuring. Lets set the amount paid to people to be near zero relative to existing salaries. So we are removing the UBI portion of your system in order to look at this monetary return mechanism.

We have a close system with very little cash and a high velocity back to the gov with all of that cash. Still rich folks can earn much more than poor folks, and they can gain interest off of assets they own, just as today.

All of their bank accounts are denominated in assets. Indeed one way for rich assets holders to make money is by leasing fractions of those assets to banks which use them for their holdings instead of cash.

Still the price of houses goes up just as now, and the rich are the ones with assets to buy them.

What have you done here other than forced an inefficiency on the banking system?

Now if you use this strongly to provide UBI it has the same effect as taxation. Consider the other extreme where we set the UBI so that UBI dollars represent 90% of all income.

This is roughly equivalent to a 90% sales tax being used to subsidize UBI. Just as with the sales tax case, the rich would be forcably equalized with the poor as the total amount the top 10% could receive could at most double the standard UBI payment even if 100% of that GDP all went to the rich.

So your system is little different than use of a flat sales tax to pay for a UBI system, except your system introduces frictions w/o benefit.