More trainings needed

after the 30km progressive run, I know that i am seriously lack of endurance to be able to complete 50km.

I have more trainings lined up before the tapering, mainly working on muscle endurance.

I have to tread very carefully on the intensity and mileage as I dont want old injuries to flare up.

Here's my plan for the next 3 weeks

hill trainings on treadmill - 1 x weekly

stairs trainings - 1 x weekly

Short or mid distance trail run (either 10 or 15km) - 1 x weekly

Mid or long distance trail run (either 15km or 21km) - 1 x weekly

Last Long run of 35km scheduled with BFG and PK on 10Oct, but yet to confirm.

Maybe weights training on non-running days.