They give you 20%+ return per year for 10 years?! How is that possible/sustainable? A ponzi scheme?
The word 'return' has no fixed meaning, although you have taken the privilege of assigning an invidious one in this case, apparently.
A more intutively descriptive term for the payments to a beneficiary from a fixed term annuity is cashflow - it is the amount 'returrned' to the beneficiary which can be conceived of in in two parts; income (taxable, usually) from 'returns' on the investment component of the transaction and 'return' of the capital used to generate the investment 'returns.'
If you run any set of numbers through this common annuity calculator,
https://www.immediateannuities.com/ you'll see that they promise cashflow -returns, if you will- in the ballpark of 20% on a five-year fixed annuity and 10% on a ten-year fixed.
That's not great appreciation- close to break even on holding cash in a bank, but these annuities are usually backed by bonds purchased by the issuer and bonds, as we all know, are not making a lot of money at the present moment either.
OP seems to have the same confusion about the word 'return' means in this context and his projections, even expressed as cashflow do seem quite high. I suspect -but can't know on the limited information given- that what he is looking at is a projection for an annuity
with a deferred start date (maybe twenty years in the future) with a certain term payout staring on that future date.
But maybe it's a Ponzi scheme. That's not the first thing I think of, but it's really up to you.