When completing a 2M sat trade on robosats, I couldn't do it with own lnd node, route kept failing even though I had a 10% max fee, more than enough liquidity a 3 good channels to very well connected nodes.
I had to send the 2M sats from my lnd to my phoenix wallet, but couldn't do it in 1 go, had to split it in 4x 500k sat invoices, otherwise the payment would fail, even though I had bought 4M incoming liquidity in phoenix.
Then from phoenix, I could finally pay the 2M robosats invoice and complete the trade.
Maybe I'm just a terrible node runner who doesn't know what he's doing.