similarly feedback for myself : I was using a Door L with my 60 kg and foilkites 22m before foiling ; it works up to very light wind (say about 7 knot in my wind speed reference) but you need to keep concentrated on staying up-wind ; you have some reward to ride on flat seas (but not glassy in open seas) , but not a lot of possibility for fun; when I switched to HF, it was a game changer even compared to this Door+22m extrem light wind quiver : with a bit of experience, I was able to ride in similar wind with only a 10m foilkite, with far more room for fun ( carving, different upwind angles, ect ...).
Door can be a way to ride if you have shallow water or if you are too old to start a new discipline or if you can only very few times a year; but ... if you have the courage to sacrifice 2-3 sessions at the start, you need to jump on a HF, it is a completely new world for light wind : lighter winds (about 1 to 2 knots less with a 15m kite) , speed (last week I was foiling at 21-22 knots in only 6-7 knots wind), freeride all along your spot, extreme smoothness (no support information which is a game changer), relative wind feeling, pure silence, alone or almost on the spot, and flat flat flat water (glassy with a light foilkite). My opinion is that it it a real pity if you are in the situation to learn foiling and do not try it ... only learning the waterstart is 2 to 8 hours frustration (depending on your spot and skills); then when you can ride (even still foil down) it is more interesting than a door.
And the kite is far smaller, hence cheaper , funnier, and easier to handle on the beach or in the water.
Now with my feedback, and even if loving foilkites for years and years, if I had a crutial financial choice to do, I would prefer HF + my existing LEI (or strutless) rather than Door/surf + foilkite in the same 8-11 knot wind range.