I haven't tried lnbits, but glancing at the docs, I would usually use the CoreLightningWallet backend, but that is only if lnbits is on the same machine.
Biasing a channel you want to balance may give you some passive balancing, as other payments go out, but unless you do lots of payments I don't think it will be very effective. Most people use the rebalance plugin, but it's a bit primitive these days: we could write a better one...