The most recent power plants such as Olkiluoto are third generation plants. Fourth generation plants are still decades away. Yes research into Fusion must continue but the plant that is being built is simply a test plant and even it won’t be fully testing until 2027, it would be decades after that before any commercial plants come into operation even if everything works. Research into both types but particularly fusion are separate from the nuclear power plants that Europe currently has. These could all be shut down without any impact on research. Moreover why spend billions on research when we already have technologies that provide clean electricity?