Just read this guide: https://www.lesswrong.com/posts/7Q7DPSk4iGFJd8DRk/an-opinionated-guide-to-using-anki-correctly
20 cards a day — Having too many cards and staggering review buildups is the main reason why no one ever sticks with Anki. Setting your review count to 20 daily (in deck settings) is the single most important thing you can do to stick with Anki long-term.
Is it possible to do this in Mochi? I've also struggled with reaching staggering number of reviews which kills motivation, and having some sort of limit (which also needs to include new cards somehow) seems useful.
SuperMemo deals with this problem using the concept of Priority Queue. The user assigns a priority value from 1 to 10 at the time of adding a new card. Then, during review, higher priority cards that are due on that day are shown first. This way, you can be sure that the most important cards are reviewed on their scheduled (optimal) date, while lower priority ones get pushed away.
Another solution would be to automatically balance the load across several days. The app can monitor cards that are due for the next 7 or 20 or whatever days, and spread the load evenly. This balancing should only be done for old cards, those with an interval of, let's say, 90 days or more. For these cards it won't matter if they were to be reviewed at the 85th or 100th day.