In T177462#4412151, @Tgr wrote:

The current load is around 1 read/sec an 0.1 write/sec, but the feature is not used on the web which would be the overwhelming majority of the load. OTOH there are some temporary limitations in place: no more than 10 lists or 100 list entries read in a single request - those would presumably be lifted if the DB permits.

Once the DB cluster is upgraded (see T177462: DB hardware for Reading Lists), we should revisit the existing limits and see if we can increase them to improve the feature.

Web usage is still far ways out and not clear when it will happen, so let's focus on the Apps and browser extension usage for now.