In case other searchers find this thread and don’t want to manually calculate as in the coming weeks more items will still be rolling out
Kumirei’s locked count script adds a ‘Locked’ category to the SRS bar
(mine’s not that informative unfortunately). The hover sums radicals, kanji and vocab that hasn’t yet been lessoned - so that’s both availabled lessons not yet taken and locked items not yet available.
My Dashboard Cockpit has a similar counter but doesn’t include available lessons (only locked items)
And R/K/V tiny bars gives you your progression for the individual categories
Although the ‘finished’ count is a count of the number of items that are Guru and up (in other words ‘passed’) rather than how many are lessoned. It does show the total number of items of course.