Refresh rate stuck in 60hz in Razer Blade 15 Advance 2021 240hz QHD

Hello all, Long story short, a month ago I decided to buy a Razer Blade 15 advance.

• Intel® Core™ i7-10875H 8-Kern (2,3 GHz/5,1 GHz) der 10. Generation
• 15.6" QHD, 240 Hz, 100 % sRGB, 4,9 mm dünne Seiteneinfassung, werkskalibriert
• GPU: NVIDIA® GeForce RTX 3070 (8 GB GDDR6 VRAM, Optimus™-Technologie)
• Integrated Intel® UHD Graphics.

For some reason when I was gaming I wondered why with a screen like these all games look the same as my other computer until I discovered that the refresh rate was set at 60HZ and disable. According to the razor support video I needed to switch my options to dedicated GPU in the synapse app, under the performance tab, and then select refresh rate but the option is not visible or available for me in the app. Then they said I can do it through windows but it was impossible, also blocked. I have followed tutorials, but I'm stuck. Any help you can give me? Best regards