Feel free to expand / confirm these factors in your problem:
- the draw is not intermittent. You get 0.17 to 0.23 A, all the time.
- details on exactly how you measure the draw? ammeter in 10A setting, in series between disconnected ground cable and battery? something else?
- regardless of measurement specifics, your new battery goes dead after a few days.

Given all that, there are not many things that could be at fault. Not many circuits on the car are unfused. You could check a wiring diagram to find and test them. Examples are the starter and alternator. An internal short in the alternator is a not uncommon cause of parasitic draws like this one.

An alternator with such a short might operate just fine other than that, and testing for current generation might still pass.

The heating from the draw will be about 2 Watts, so will not be obvious.

I would use a clamp ammeter (partly because I have a few of those already; but I'd buy one if I did not, to solve this problem) to measure current flowing in the wires up in the engine bay, in particular to the alternator.

Even if it is not the alternator, you could use the clamp ammeter to follow wires at each branch, starting at the battery, to see where the current is still flowing. And this is done non-invasively to the circuits.

When checking circuit diagrams for these cars, the 3.0i and 4.4i have very different layouts for the engine. So be careful what web info you find on this. If you find something that does not claim to apply to the 3.0i vs. 4.4i, be assured that it will be incorrect for at least one of them.

It may not be easy to get to, but if you wanted to do something without doing circuit research or buying a tool you don't have, you could try disconnecting the connector and cable to the alternator (i.e., disconnect that rather than disconnecting your battery to prevent the battery from going dead), and see if that stops your flat battery problem.

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2001 X5 3.0i, 203k miles, AT, owned since 2014