I experimented a few years back with “collapsing the stream” between the two posts. I think this works well on mobile. Cause it is easy to expand the stuff in the middle after you click it.
Before clicking in “in reply to”
post 1
post 2
post 3
post 4 [reply to 1]
After clicking
post 1
[ 2 more posts, click to expand ]
post 4