Only thing I’d add is to make sure that, for those who make above a certain income (the “rich”), any tax owing must be paid in full before the UBI is paid out. This prevents the float issue from coming back for those who pay late.

No need. Interest and penalties on the unpaid taxes amount to significantly more than the float.

UBI should be treated more like a dividend paid to a shareholder. The shareholder’s financial situation is irrelevant to what the shareholder is owed.