Is there a free app where you..

[adviceneedec]

Can take a photo and it will suggest decor?

Need inspiration!

Yep
Its called Mumsnet 😀

Yes! Remodel AI is great for this. You can choose your style or type in a description of what you want (under customise). It can be a bit far fetched at times, given it's AI, but gives great ideas for decor. I think you get about 8 free goes before having to pay, so worth a try.