I'm going todo a test myself using Volto 17 and volto-tabs-block.
The reason I've asked about how many listings and if they have pagination is the fact that you need to add the tab block from eeacms to the setting
containerBlockTypes
See this pull request where this was done in core in order to read the
listing block pagination when it was placed within a grid block
EDIT:
This won't work as the construct from Volto expects the blocks to be on the root of the block within the blocks key, while in tabs or accordion you have a more complex data structure as you can see in this screenshot
The logic is that if there is only one listing block or one search block the pagination
argument in URL will be ?page=1 but if there are more than 1 then you get the advanced pagination attribute that is the uid of the object - block uid.