Long run advice

I am running a marathon Oct 8th and have been consistently running 30-40mi weeks over the past several months. I have done some long runs but feeling like I should get a few more (i.e. 2-3 more 15mi+) on the legs but don’t want to cut it too close and have any of those long runs eat into my taper.

I just completed a 15miler this past weekend and now have 4 weeks from here before race weekend. I am targeting doing 18mi this coming week then perhaps 20-22mi the following week. Depending on when I do the 20-22mi that following week, I will still have roughly 12-14 days to taper. But still wondering if that is cutting it too close to have my longest run.

I’ve completed two marathons previously and typically like to give myself a solid week and half to two weeks taper. But I also understand the huge benefits of the long run and I sometimes used them as a confidence booster too. Any thoughts/suggestions are very very welcome!

Thanks!