How many raka'ahs of taraweeh did Umar(R.A) initiated?

I know that the topic of taraweeh is controversial amongst Muslims. I don't want to go in much details but I have only few questions. Here I wanted to ask about hadith in muwatta imam Malik in which Umar(R.A) ordered Ubayy ibn Kaab and Tamim ad-Dari to lead the prayer in 11 raka'ahs. Ahle hadith use this as evidence while Hanafis sobject to this that this narration is mudtarib due to its other chains. Is there objection valid? I also wanted to ask that was there consensus of compaanions(r.a) on 20 raka'ahs and is 20 raka'ahs supported through consistent practice as claimed by hanafis?