Connecting as external monitor to windows laptop

So. ill try to make this as clear as possible. I have a imac a1312, with set password, I cant get into it, but i dont actually need , because i just want to use it as external monitor. I've tried to connect it to my windows desktop pc with mini displayport>displaypor cable, and it works without issues. i just connect it, and imac shows image right away. Now my needs changed a little of bit, and i want to connect imac as external monitor to windows laptop (win10 or win11) , i have several of them. So i bought Mini displayport>HDMI cable (because all my laptops doesnt have displayport slot), and once i connect cable to laptop. nothing. FN F2 or other combinations doesnt work. i tried same cable with my desktop, and it doesnt work too. I tried tons of adapters ,still no success. i tried all my cables to another devices , just to be sure all of them is working. so it seems, imac accepts only mini dp>dp cable? hard to believe that any tips or suggestions?