Darn it's really unforunate, but Gelid just stopped its sale on the 1mm for the one I bought before. This product was $13.99 like a few days ago:

https://www.amazon.com/Gelid-Solutions-GP-Ultimate-Installation-Conductivity/dp/B08PKKMX76/ref=sr_1_3?dchild=1&keywords=gelid%2Bultimate&qid=1626549934&sr=8-3&th=1

You might have to resort to this:

https://www.amazon.com/Gelid-Solutions-GP-Ultimate-120x20x1-0mm-Installation/dp/B08PKQFT2P/ref=sr_1_4?dchild=1&keywords=gelid+ultimate&qid=1626549982&sr=8-4

But that second one is a bit too thin being only 20mm in width.

If you're in the US here is also one that I would recommend:

https://www.amazon.com/Frosty-Ice-Cube-Plus-Thermal/dp/B096G5FJF8/ref=sr_1_3?dchild=1&keywords=frosty+thermal+pad&qid=1626550032&sr=8-3

Per $/sq mm it's really affordable right now.