Below you can find the "first final" version of my KNIME cryptocurrency agent.
This is what it does :
loops through a Rules database table, which contains trading pairs and buy/sell thresholds plus percentage of holdings to buy or sell.
if a rule is triggered, places a market order to buy or sell, logs this to the Order_log database table and sends me an email.
if a rule is not triggered, logs this the No_order_log table.
As mentioned before, this uses the Revolut X trading API, as this is the one I happen to use.
To make this work with other APIs, the only nodes that should be modified would be the 2 Python Script nodes. (see first page of this topic).
I have scheduled this workflow to run every day. In a few months' time I will report on the results ...