Beaver Builder has no limit on the number of rows you can use in a layout. If you find that you can't add rows to a page beyond a certain point, check for the following:
Are you trying nest columns? You can't recursively nest columns. If you keep trying to drag a module into another column and it doesn't appear there, you've probably exceeded the nesting limit.
One way to solve this if you have a complex column structure is to create your layout with blank columns, then drag your modules into that new structure. It's easier to keep track of what's nested.
If it seems like you've hit a row limit, where you can add or save any new rows you add, try increasing the value of the
post_max_varsvalue in a php.ini file.
If you're not sure how to do this, your hosting provider should be able to help.