make your recovery discs before you do anything crazy. 2nd: W7 might work on the machine but things like the cd rom or sound controls, wifi, ethernet (the stuff in the device manager) probably wont. The computer companies dont bother writing drivers for  the old OS since it's got the new one OEM. you'll have a computer that will be in permanent safe mode. This isnt the case with custom built desctop PC's but laptops are pretty unforgiving about this stuff.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740