You are in the "classic" dilemma, same situation as almost every single hydrofoiler experience.
To be able to foil in the lowest possible wind, you need a really good race foil kite medium to big sized (around 15 m2 for your average weight).
If you get a kite like that, even if bigger, you can not ride in 3 knots.
You will need at least 7 knots probably, as such a kite is really different and you have to learn to use it to the max, and to avoid it from dropping in the water (which will happen a lot, so many packdowns and swims).
When you are experienced you should be able to ride in maybe just under 6 knots with such a kite, with the right hydrofoil.
Then you can choose an easier foil kite, that can be on the water longer, without taking water, and handles a lot better not collapsing either.
These kites will require a tad more wind as they are not tuned to the max, but a lot easier in every way.
Finally you can choose a LEI - as the last 3 years many has been developed these almost solely for hydrofoil, but can be used for any other light wind board too.
These, say a 12 or a 15 m2 Storm Voyager, or a BM Cloud and there are other strutless kites.
Or go for a 1 strut light kite, or even a 3 strut light kite - they have a huge windrange and are all super easy to handle.
But you will not get the ultimate low end, you will probably need just under 7 knots to ride with such a kite, where a racefoilkite can go just below 6.
The advantage is of course the easy handling, and they hang just as well or better as the racefoilkites - and if you drop it you can just relax and drift ashore for a relaunch.
They turn much faster and good for "fun" - but on the other hand, if you seek the very marginal low end, you are probably not able to make that much fun stuff, apart from riding and doing tacks, so here a foilkite would be better one could say.
Just my views - two (okay three) very different kite types, but they all work great in sub 10 knots, where you are right, all "normal" kites are pretty useless here as too heavy.
For your current experience, I dont think a foil kite will give you that much now - but it wont take long till you get the experience and can take advantage of a foil kite, when you have learned to use such an animal (takes some time, they do NOT ride or handle like a LEI in any way)