OCSP is going end-of-life because it makes it too easy to track users.
From Lets Encrypt[1]:
We ended support for OCSP primarily because it represents a considerable risk to privacy on the Internet. When someone visits a website using a browser or other software that checks for certificate revocation via OCSP, the Certificate Authority (CA) operating the OCSP responder immediately becomes aware of which website is being visited from that visitor’s particular IP address. Even when a CA intentionally does not retain this information, as is the case with Let’s Encrypt, it could accidentally be retained or CAs could be legally compelled to collect it. CRLs do not have this issue.
[1]: https://letsencrypt.org/2025/08/06/ocsp-service-has-reached-...