Hello,
Yes, what 3java3 suggestion is the best to do it. What other people observe at perfect Aeroglass look, might not for others. Do the 30 days trial and download some Windows 7 themed WB skin, try it out and see if it work for you. As for completely transparent theme, Windowblinds can do it, not sure if it look good on actual skin though.
Do know that, there are parts in Windows 10 and Windows 11 can not be skin/change at all. So, don't expect Windowblinds alone can make your Windows look 100% Windows 7.
Thanks
Basj,
Stardock Community Assistant.