Original question was to use single kite in winter and summer. I would not count Peak as single kite offering. Although good point of Peak is that it is very affordable. Same goes for open cell foils.
So for original question the options are closed cell foils and inflatable kites. Both work at summer and at winter. On both worlds, closed cell foil and inflatable, there are numerous brands providing a bit different gear with different qualities.
Also the wind range (10-25) is quite broad if we consider different surfaces. On wet soft snow the proposed 10m could be too small for 10kn winds, on pure ice anything which flies is ok. Also considering 10kn water conditions you give as a clue.
I don't know how you think about kiting vs wind surfing. Are you going for wind surf at 20kn and above, so 25kn is upper gust limit for kite or do you plan to kite at 25kn + gusts? And you say on your are you have very seldom +15kn winds.
My proposal would be to go for 12-15m kite if 25kn is the upper gust limit and you prefer wind surf on higher winds (+18kn). On summertime as a beginner you need much more power at 10kn winds than not-a-beginner kiter.
For most broadest windrange and winter + summer usability I would recommend you Flysurfer Speed4 15 (or smaller 12) as a single kite option. But I admit they are on a bit costly side but if you can afford to windsurf with many sails/boards/means of transportation
. Or second hand Speed3 15DLX from reliable source. With reliable source I mean that you get tuned kite and not out-of-tune one and the kite still has hours left.
It would have the wind range you request with emphasis to lower section you mention (10kn) and as you mention you rarely have +15kn winds. On my winter area we mostly have 3kn-12kn and sometimes heavy inversion with 0kn at surface so you need a kite to be able to launch and fly at those conditions and Speed-kites are the ones. Inflatables usually want to hinderburg down because they mostly are nose heavy if able to be launched at all.