In Nightsilver

There are 48 point bundles which give 250bp shards each.There are also 9 XL bundles which give you 2000bp shards each.That's (48*250) (9*2000) = 12,000 18,000 = 30,000bp shards (equivalent to 30 bp levels) for nightsilver alone.

In Foulfel

There are 42 point bundles which give 125bp shards each.There are also 9 XL bundles which give you 1000bp shards each.That's (42*125) (9*1000) = 5,250 9,000 = 14,250bp shards (equivalent to 14 bp levels) for completing foulfel

So in total you get 44.25 levels for completing both cavern crawls!

Just in case you were wondering how many levels you could get by playing cavern crawl.

Extra tidbit: There are over 200 rooms in total (100 for Nightsilver and 100 for Foulfel) and you have 100 days of battle pass left. So you'll have to clear approximately 2 rooms per day in order to get all the rewards before bp is over.