That will be a challenge: since VTXOs are UTXOs, they are bound by the dust limit.

In other words, you will not be able to unilaterally exit a VTXO with value less than the dust limit, so it would not be trustless.

Of course you could receive several low value VTXOs and trust the server it will allow you to swap all of them later for a bigger VTXO.

It's not 100% trustless, but you only need to trust the server for very low amounts. It could work.