Yup. Turns out you're correct! Thanks for pushing me in the right direction!!

Hello, I'm looking for help on a project I'm working on. This is my first time posting on the Bitcoin Forum. I'm not sure if it's appropriate to ask for help in this way. I have also posted this on Reddit - but I suspect as this question (to me at least) is somewhat technical, I may get better advice from a more specific (or sophisticated) crowd. 

My intended goal: use Sparrow Wallet and Seedsigner to create a 2-of-2 multi sig wallet that after a certain amount of time becomes a 1-of-2 multi sig wallet, such that either wallet can sign a transaction on its own.

To be clear, my intended policy is:

Both RED key and GREEN key are required to sign a transaction prior to a certain date (in this case July 5th, 2037, which is unix timestamp 2130393600)
AFTER 2130393600 either RED key OR GREEN key can sign a transaction alone

I've used ChatGPT to help me with this. This is the miniscript it came up with:

wsh(thresh(1, and(and(pk([REDfp/48h/0h/0h/2h]xpubRED.../0/*), pk([GREENfp/48h/0h/0h/2h]xpubGREEN/0/*)), after(2130393600)), pk([REDfp/48h/0h/0h/2h]xpubRED.../0/*), pk([GREENfp/48h/0h/0h/2h]xpubGREEN.../0/*)))

I believe the miniscript is correct.

The problem is that I'm not able to get Sparrow Wallet to create the wallet using this miniscript. I'm using Sparrow 2.1.2.

After placing the script in the "Edit wallet output descriptor" and hitting "OK", sparrow wallet seems to accept the script (or at least I get no error messages). However, it does not create the wallet with the intended policy as I've stated above.

The Descriptor on the main settings page reverts to "wsh(sortedmulti(1..." rather than "wsh(thresh(..."

I've spent hours trying to troubleshoot this problem with ChatGPT and have ultimately been unsuccessful. ChatGPT seems to believe if I'm still getting "wsh(sortedmulti(..." that it is a syntax error.

Do you have any advice? Any ideas on solutions? Any help you can provide is very much appreciated!!

This is the link to the reddit post if looking at a few screenshots I've taken for this question are helpful:
https://www.reddit.com/r/Bitcoin/comments/1ku4cmm/help_help_with_sparrow_wallet_descriptor/