The Headers interface of the Fetch API allows you to perform various actions on HTTP request and response headers. These actions include retrieving, setting, adding to, and removing headers from the list of the request's headers.
but keep in mind they will still evict things early based on plan priority, for example free zones will get their cache evicted the instant cloudflare needs more storage
Yes, that value does not go to 2 years. But does it matter? I highly doubt most browsers are going to keep a cache item around for that long without doing their own eviction anyway.