Sticky Gel Pads (10 Pack), As Seen On TV Removable Traceless Gripping Pad Washable Reusable Anti Slip Pad for Car Dashboard Office Home Stick Anything Anywhere, Clear

Here's a solution (What I'm using now) but after a few days you need to put pressure on them again: https://www.amazon.com/dp/B07PFW5SXB?ref=ppx_yo2ov_dt_b_fed_asin_title It's what I'm using now. They don't leave residue, and I think you could improve it by putting a thin magnet on them and applying a magnet on the other side once you put the shade in. Could likely get it to stick for quite a while with that. I just don't like having them on the window when I take the shade off. They come off easy though, but overall not perfect.