Here's your first plan, 15 weeks until the marathon on 20/12, starting tomorrow itself (Tuesday). I'm building from your last 90 days: you've been running ~45 km/week with long runs already of 20-22 km and regular intervals/tempos, so I'm NOT giving you a beginner plan — I'm building on the easy volume you already handle plus ONE quality day per week, gradually ramping up toward your marathon peak. I've assumed two things: (1) that 3:45:00 is a realistic goal for you today, consistent with your recent 10K of 48:00 — if it's more of a "someday" goal, tell me and I'll soften the target pace; (2) that your threshold pace is around 4:55-5:00/km (with easy running at about 6:00-6:15/km and marathon pace at about 5:20/km) — if you have a measured threshold let me know and I'll recalibrate the whole plan on the spot.
Structure: soft base these first 6 weeks (progressive, continuous tempo and cruise rotating on Tuesdays), then a build phase with over/under and ladder work, a marathon-specific block with stretches at goal pace inside the long run, and real taper the last 2 weeks — race week includes a sharpener at marathon pace on Tuesday and short intervals on Saturday, never just easy runs. Strength stays on Friday, 1x/week as you asked, and disappears in race week.
I've put a recovery week every 4 weeks (weeks 4, 8, 11) so fatigue doesn't pile up — it's normal those weeks feel shorter, that's the idea.