right after that the rating is there
this is an example on how to retrieve it:
public data API returns wrong ratings

But that doesn't explain the mismatch Omed and I don't think the OP is asking for help to obtain 'best' ratings?
Why is that player's most recent ('last') Rapid rating shown as 2069 on their webpage stats but only 800 in the endpoint? There seems to be something badly adrift there.

I have also seen this happen before, but could not catch it. By the time I checked it had been corrected.
The time stamp on it is "Friday, 21 July 2023 02:45:38". Probably a cache update will fix it soon, but it would be good to fix this bug.

But that doesn't explain the mismatch Omed and I don't think the OP is asking for help to obtain 'best' ratings?
Why is that player's most recent ('last') Rapid rating shown as 2069 on their webpage stats but only 800 in the endpoint? There seems to be something badly adrift there.
im not sure but it seems to be only rapid ratings, because when you go to, https://api.chess.com/pub/player/omed/stats the last rating for rapid for me is not right either.¯\_(ツ)_/¯

"..the last rating for rapid for me is not right either"
Curiouser & curiouser!
this is really weird because in some apps like chessinsights.xyz the elo graph is now broken...

At https://api.chess.com/pub/player/defaultedwastaken/stats , it says
"chess_rapid":{"last":{"rating":800,"date":1689907538,"rd":48}
but on
https://www.chess.com/member/defaultedwastaken the user's rating is shown as 2000, which seems to be correct. What's going on, why is the rating incorrect in the API?
Looks to have been corrected.

At https://api.chess.com/pub/player/defaultedwastaken/stats , it says
"chess_rapid":{"last":{"rating":800,"date":1689907538,"rd":48}
but on
https://www.chess.com/member/defaultedwastaken the user's rating is shown as 2000, which seems to be correct. What's going on, why is the rating incorrect in the API?
Looks to have been corrected.
its not corrected?

When I posted yesterday it definitely showed the correct current rating. Now it's reverted back to 800.

Have you put in a support ticket?
There is another anomoly. The unix time stamp for the 800 rapid rating in July 21st and there are games played after that.
Getting more and more weird. The only rapid game on the 21st was unrated.
At https://api.chess.com/pub/player/defaultedwastaken/stats , it says
"chess_rapid":{"last":{"rating":800,"date":1689907538,"rd":48}
but on
https://www.chess.com/member/defaultedwastaken the user's rating is shown as 2000, which seems to be correct. What's going on, why is the rating incorrect in the API?