Does got any optimise method can swap/splice/loop channel without on-chain cost ...

if I got custom Node and Alice has 3btc and bob got 0btc and bob got 0btc with Tom 1 btc. Is it possible we can change channel for Alice 3btc with Tom 1 btc. And close Tom. And it doesn’t go to on-chain btc. Does it possible Only swap this in off-Chain my node?

If initially the channels from Alice, Bob and Tom came from the same channel factory (we do not have channelfactories as part of lightning as they would be much easier to build on eltoo channels) then I guess Bob could easily be removed off-chain to have a new channel just between Alice and Tom. As with current lightning network I think we have to hit the chain to achieve what you want