Maybe? I don't know what splicing is, but if it cooperatively moves part of the channel funds to a new address and reduces the channel size accordingly, that'd make sense. It looks like, from a technical perspective, it is possible in a trustless way:

Knowing Bitcoin

Lightning Payments in Practice: Sending, Receiving and Troubleshooting - Knowing Bitcoin

Lightning Payments in Practice: Sending, Receiving and Troubleshooting: lesson from the Lightning Network & Bitcoin Nodes course on Knowing Bit...

It turns out boltz wasn't just an altcoin swapping thing, but it also allowed trading BTC in lightning for BTC on-chain. But as someone else in this thread mentioned, they're gone. There's reportedly software called Loop, which Loop Bitcoin service is a self-hosted thing that will solve this problem (I didn't look into the technical details, but presumably it works the same as bolz, with the hash lock).

And yes, I guessed what splicing is correctly.

Splicing

A technique to add or remove funds from a Lightning channel without closing it, maintaining channel uptime and routing capabilities.