I had been using iCloud Private Relay for most of the last year but have stopped using it about a month ago.
There had always been some random slowdowns but after iOS 17 update it was constantly waaaaay slower than iVPN. For instance I did multiple speed tests over several days and IVPN was getting around 250-280 megabits compared with a little over 300 with no VPN.
iCloud relay was down to 20. No not 200, twenty megabits per second.
I have switched to just having IVPN on instead.