Old spa bath jet covers



Hi there, can anyone help with a solution to cover up these old spa bath jets - the tops have been removed (difficult to clean, would get mouldy) and ideally we’d love to cover them up with something relatively flat that was easier to clean.
We have found a pipe part thing that screws in and fits (pictured) but it obviously sticks out a bit. We have tried cutting it but can’y get a smooth cut. The pipe cutters available at bunnings only seem to be for smaller pipe.
Any ideas on how we can cover these up?