Stablecoins and things like tokenized stocks and bonds are considered as "backed" and classified as "Group 1" cryptoassets by the BIS. As such, there are no limits to their exposure to these, as long as they satisfy a series of conditions.

The 2% limit (and "1% exposure" recommendation) applies to "Group 2" cryptoassets, which they say are "not backed" by anything, and include BTC.