Something like the Total Progress Bar script may help (it was originally made for level 60’s, but lower-level folks can use it too, and items that are locked or in lessons show up as grey by default) as it fills up with different colors depending on all the items you have at different SRS levels. I don’t use it myself, I use Burn Progress which uses light grey for locked/lessons, light gold for “seen” items, and gold for burned items, so it’s a little simpler. This is what mine looks like right now:
I think there are other scripts that show total progress too, like with graphs or charts, though I don’t know any offhand. But one of those may help with showing that you are indeed making progress even though your lessons keep refilling.