I can't pick a favorite since I use the following all the time for volleyball and other indoor sports:
200 f/2
120-300 f/2.8
400 f/2.8
70-200 f/2.8
Much depends on size of gym and media photo access areas.
The most versatile is the 120-300.
The 70-200 f/2.8 is perfect if you can get close.
The 200 f/2 is ideal for lowlight and when you need ultra fast focus on a mirrorless body.
The 400 f/2.8 is my favorite when there is room.
NIKON Z 9 VR 200mm f/2G lens 200mm f/2.0 1/2000s 12800 ISO 0.0 EV
NIKON Z 9 VR 200mm f/2G lens 200mm f/2.0 1/2500s 12800 ISO 0.0 EV
NIKON Z 9 400mm f/2.8D lens 400mm f/2.8 1/1600s 10000 ISO 0.0 EV
NIKON Z 9 400mm f/2.8D lens 400mm f/2.8 1/1600s 12800 ISO 0.0 EV
NIKON D6 VR 70-200mm f/2.8E lens 70mm f/2.8 1/1600s 8000 ISO 0.0 EV
NIKON Z 9 AF-S NIKKOR 120-300mm f/2.8E FL ED SR VR lens 280mm f/2.8 1/1600s 12800 ISO 0.0 EV
NIKON Z 9 VR 200mm f/2G lens 200mm f/2.0 1/2500s 12800 ISO 0.0 EV
NIKON Z 9 400mm f/2.8D lens 400mm f/2.8 1/1600s 10000 ISO 0.0 EV
NIKON Z 9 AF-S NIKKOR 120-300mm f/2.8E FL ED SR VR lens 300mm f/2.8 1/1600s 12800 ISO 0.0 EV
NIKON Z 9 400mm f/2.8D lens 400mm f/2.8 1/1600s 10000 ISO 0.0 EV
NIKON D6 400mm f/2.8D lens 400mm f/2.8 1/1600s 8000 ISO 0.0 EV
NIKON D6 VR 70-200mm f/2.8E lens 105mm f/2.8 1/1600s 8000 ISO 0.0 EV