Hello,
I have not replied earlier to you because I am extremely busy at the moment.
To answer your query, I am not considering option #2 as it is way too complex. The plan is for me to release the long awaited exchange extension as soon as possible. This is the first priority. Then, if people want to enable currencies such as USDT or TUSD, they will be able to exchange between fiat and crypto.
The plugin will not provide a way to directly purchase cryptos with fiat as this is out of scope.
kind regards
Alex