If you can’t remove then you will have to patch and i will tell you from experience it is not easy to do as each ceiling was done by a person that had their own tools. Can this be smoothed by just remving the texture or just have adywall guy come out and see if it can be smoothed with drywall compound

If you try and patch it up that will be
challenging to match the pattern, maybe you want to see about adding the
thinnest drywall( 1/4" thick) and install on top of the plaster ceiling.
Might be cheaper than removing texture plus less dust and mess.