slow attachment pages

You’ll have to add the cache group to the WP_REDIS_IGNORED_GROUPS config:
https://github.com/rhubarbgroup/redis-cache/wiki/Configuration-Options

By default images aren’t stored in Redis, this must be a 3rd party plugin doing it.

@tillkruess

Like this?

define('WP_REDIS_IGNORED_GROUPS', ['attachments']);

Yes, except you need to find out what the group name is. You can probably use redis-cli --bigkeys to find out.