I thought that members only needed to be sworn in at the start of each Parliament (not each session), or on a succession to the Crown. All Lords were duly sworn in 2024 (or 2025 / 2026 when they first sat in the session). Those that didn't have either been removed due to non attendance or are on leave of absence, so no-one needs to be sworn in at the moment until they return from leave of absence, or we get some new peers.
I presume that all hereditary peers that return after being created a life peer will need to swear in again, in line with the practice for the life peerages for the Earl of Kinnoull and the two Lib Dem hereditaries.