windows and r-value?

I have a situation where a company wants to convert some space into a break room. It has a south facing window that gets direct sunlight and can get very hot. A suggestion was made to add the styrofoam insulation boards over the window to help.

My question is how effective is new window films and treatments at keeping heat out compared to insulation board? I know there are various types of films out there that block uv and some evendors block infrared waves. I’m hoping someone who knows this subject can point me to some info or references so im not so ignorant.

I’m wondering if film that blocks 100% of radiation will work just as well as insulation board? I realize convection of heat might be an issue through glass but would that be upto exterior ambient temperature?

We have had silver coloured film on most of our windows .
We are pleased with it. Some birds do fly into the windows most flay away .
If they want more control I think insulated white drapes could be an added to help when the sun is shining on that part of the home .
Yes I would do it again Roy Cost was about $800;00 to do most of the home .
We did not do out sliding patio doors as the have venation blinds in between the windows .Again love them and they work great.

up the topic