I recently started using Todoist (Pro account) and never heard of these limits, but indeed here they are:

https://todoist.com/help/articles/todoists-limits-for-tasks,...

I haven’t got my projects fully populated yet but 300 is definitely possible for some, eventually.

When I look at the enumerated limits I suspect a code/database issue rather than bean-counter logic… surely you can pack a whole lot of text into your cloud sync for 5 USD per month less Apple tax?