I was wondering if Quest 2 straps could be made compatible to the Quest 1. Indeed, it is possible. I liked the design of @sekazi (https://www.thingiverse.com/thing:4624192), but the adapter is movable, so I decided to make it 2mm longer and added a small clip at the end, so it does not get off the quest itself.

I tried with a 25€ strap from Amazon and it works fine - at lot better for big heads than the original strap ;) Worth printing! You may need to put a bit of hot glue on the strap, when clicking it on the adapter, to ensure a good connection.