Bcoin initial blockchain sync progress isn't saved
I think the configuration you are missing is

memory: false

See the default full node application script here: https://github.com/bcoin-org/bcoin/blob/cec3c3e788834d3e9fc3c0b21bc3e340d573dcfd/bin/node#L31

By default, bcoin objects (like chain and walletDB) run in memory.

So actually I'm curious what is taking up the 10GB in that directory? Could it be data from a previous run with a different configuration? There could be a bug, but just looking at the script you have posted here, I would expect the Full Node to run entirely in memory and therefore start over on each execution.