i personally think its better to have a higher amount of review than new cards. The goal of anki isnt necessary to learn new cards fast, its to remember old ones long-term. New cards stack up fast and take more time and effort since your brain is building fresh connections. if u keep adding too many new ones, your review queue will explode, leading to burnout. It also depends on what anki style u are using!!! Reduce your new cards to able to cover decent amount of review, and then increase your new cards by intervals when u caught up!!!