There are caps (limits) in place too. Usually set by the ad campaign. The time limit for caps vary, they can be daily or weekly, and you can max out of an ad campaign too! In addition, the number of ad campaigns you are eligible for may be limited by criteria set by the ad campaign, including what country you are from and what OS you are using. You could get a ton of ads one day and nothing for the next 3 days! It all depends on the ad campaigns you are eligible for. Additional links below if you want to find out more info.
Default Max Limits at brave://version -->Variations:
Variations
AdServingStudy:DefaultAdNotificationsPerHour=10/MaximumAdNotificationsPerDay=100/MaximumInlineContentAdsPerHour=12/MaximumInlineContentAdsPerDay=60
Other sources with additional information:
Discussion topic with above links
What determines the number of ads per hour
Please remember, max means the max amount you could get, not the max amount you will get! You could get zero. Help Center article for reference: Why don’t I see any Brave Ads after enabling them?
You can check the ad campaigns (and some of the limits in place) here: Regional Catalog Viewer