Seems to closely fit with what has been reported in the past.
“According to Forbes, the crown, through the the Firm (which actually goes by “Monarchy PLC”), holds nearly $28 billion in assets.”
https://www.cosmopolitan.com/entertainment/celebs/a38266323/queen-elizabeth-ii-net-worth/
I know most of the palaces and lands aren’t really theirs and the crown jewels don’t belong to them either.
I could be wrong, but such a relatively low figure for a family that has been ruling a kingdom for 80 years or more almost makes it seem that their finances aren’t well managed at all.
I think a typical family, after 80 years, could do better than that.