I posted my answer in the original thread:
I found the solution. Visit this link and search for “Timescale” Keyframing | Unreal Engine 4.27 Documentation
You can also time scale sections, which will scale the keyframes proportionally to the scale amount. Hold Ctrl and drag the edge of a section to timescale a section. Time scaling is denoted by a clock icon beside your cursor when holding Ctrl and hovering over the left or right edge of a section.
If you need to scale to an anchor point, then you probably need to add a cut in there so that it’s a separate timeline. I haven’t used Sequencer in a while so I don’t know off the top of my head how to do it, but it is possible to have multiple timelines embeded.