If you consolidate 20 inputs into 1 output then, unless taproot or multi-sig as destination is used, all inputs are probably owned by one person.
Can you give me an example of private consolidation with wasabi? I do not understand. You mean after the coinjoin or during coinjoin?
During coinjoin. You can see how 12 UTXOs were consolidated in this coinjoin transaction:
Take this WabiSabi coinjoin that confirmed in the last block for example:
https://mempool.space/tx/921ad5bfd23403e04682222387608b6231ef715cc4ce079ffd1644f2480dab37There's 237 inputs and 225 outputs in this coinjoin (net consolidation of 12 UTXOs). If OP consolidates his 20 inputs within this transaction, how would anyone be able to determine that those 20 inputs belong to him? You can't tell how many users are involved in the coinjoin, or which inputs are commonly owned by each user.
If this were a normal transaction, you would assume all 237 inputs were owned by the same user. But, since it's a WabiSabi coinjoin, you can't determine how many users are participating, or which inputs belong to each user.