How is the Zakat on money calculated if the money reaches the Nisab by adding previous savings to recently received deferred financial entitlements, knowing that each amount on its own did not reach the Nisab upon its receipt?

If you did not possess the minimum threshold (nisab) before receiving the amount of your rights, then there is no zakat due on it, nor on the small amount you previously had.

Begin calculating the zakat year (hawl) from the day you acquired the amount that completed the nisab. Then, pay the zakat upon the completion of the year if the nisab has been maintained throughout. As for amounts below the nisab, there is no zakat due on them.

Therefore, if you acquire wealth for which a hawl is typically considered, and you possess no other wealth, and this amount reaches the nisab, or if you have wealth of the same type that does not reach the nisab but does so with the newly acquired amount, then the zakat year begins from that moment. If a year passes, zakat becomes obligatory on it.