I am losing weight at the moment, yes, but even when I'm finished, I would not go back to a full 2100kcal per day - I'm not active enough to burn that off, so I would need to have a lower calorie intake. So, this is not a short-term solution.
And no, I'm not taking a multi-vitamin tablet.
Instead, in the absence of a pre-packaged solution, I decided to create my own nutrition calculator (I'm a programmer), which can be adjusted to different requirements and will list common off-the-shelf ingredient mixtures that add up to the daily requirements. It already works.