How can curl_multi be kept within 5 rps?

Question

linux

I made a function with multicurl that takes an array of links, the array is always no more than 5 elements. The function returns the totaltime spent on 5 links. If the totaltime is less than 1.0, then I subtract the totaltime from 1.0, and convert the difference to microseconds and send the difference to usleep as an int (i.e. I stop the script for the number of microseconds that were not enough for a whole second). After that, the multicurl twitches again. But in some places it's still a response from the recipient with the code 429.
How can you get out of this situation other than sending the request again if 429?

Answer 1

And what about rps?
1) Add different browser http headers. may I help.
2) Catch exceptions and resubmit the necessary requests.