I also bought https://www.amazon.com/gp/product/B07RMDWJ5C/ and https://www.amazon.com/gp/product/B0000CBIFF/

Put foam on the plastic shield of the AC unit to get a better seal, then tape it up.

If you're in the USA: https://www.amazon.com/gp/product/B0000CBIFF/

3m interior window weatherseal tape -- works like a dream, super flexible and easy to remove.