Like let's say about Fortnite, which of them is like "better" (not playing it, but as an example)Generally no but might depend on what you mean better. The 1070Ti with 3900x could get higher fps at lower game settings/resolution due to faster single core performance of the cpu but in other scenarios the 2070 with 2700 is going to win.
Depends on the resolution and refresh of monitorLike let's say about Fortnite, which of them is like "better" (not playing it, but as an example)
1080p 240hzDepends on the resolution and refresh of monitor