compare blobs vs legacy (total sync time)

we need to ask the fundamental question:

• How does blobs behave compared to legacy, in terms of ... sync time (#8891, #8892, #8893 deal with other metrics)

Let's use 3 different scenarios:

• many small "docs" (5K)
• fewer bigger docs (500K
• much fewer bigger docs (5MB).

(#8884 (closed) is related to the definition of those different scenarios). We could highlight only one case to be showcased in the speed-center representation (the one in the middle).

I think we could run the same bench/e2e against 2 providers, one with blobs enabled an other w/o. (OR the same provider but using the soledad blobs flag in the initialization, easier)