Someone mentioned the Schotiss blinds on amazon from IKEA.
DS and I are autistic, light and heat sensitive and these are what we use on our large west facing window.
I also have 2 fans. An 18" industrial fan sat on a north facing window, though a south facing window is also fine, facing outwards, window open, blowing the hot air out.
We have a second rechargeable fan that is higher powered that we use facing us.
We freeze 2l bottles of water and put them behind it to cool the air down as it is pulled through, and rotate bottles so as soon as one is melted it goes back in the freezer and another one comes out.
Less advisable, as you cannot reuse them for hot water in winter due to risk of splitting, but we freeze water in hot water bottles, wrap them in a towel and they come with us where ever we go in the house. Sofa, bed, etc. I even shove them down my top when it's just us in the house, and walk round like I've got an ice-baby.
We have those handheld mini dyson looking neck fan things. The one with the lanyard, and adjustable neck. £8 each off tiktok but can probably get them anywhere online.
Crazier things I've tried in desperation in past years include aloe vera gel sanitary towels, like the ones you make for postpartum, frozen, then down each bra cup. Be careful not to give yourself freezer burn. Freezer bags with wet sponges in them, frozen, then wrapped in a thin cloth, still in the freezer bag, and stuffed where ever you need it.
Invest in some loose fitting, long sleeved, long legged linen clothes for precisely this sort of weather to protect your skin, wick sweat away, and give space for evaporative cooling. I know long sleeved isn't what you'd choose in this heat but it does help, especially if you have East and West facing windows.