We ran a number of tests, including sending a percentage of real traffic to endpoints running AWS-LC and Wolfssl. Technically yes, OpenSSL 3.X is slow, measurably so, but not enough that we wanted to deal with it. That's for our use case, I can easily imagine there being others, where maybe you have different hardware or way more traffic, where it would be worth while. For basic TLS termination in haproxy, it wasn't really worth it to us.