If you’re going to transplant, do this....
Make a hole in your larger pot and set the solo cup into the hole so that the soil levels match. Next, snug the soil around the side of the cup (or a separate solo cup, if you want) and twist the cup around a couple times before you pull it out, carefully. You should have a perfectly shaped hole that’ll fit your plant perfectly. Then, using scissors, cut the top lip/edge of the solo cup (with the plant in it) in about 5 places; and, using a razor blade or exacto knife, continue the cuts by making a slice straight down the side of the cup- from those top cuts to the very bottom of the cup. Now you can hold the solo cup in one hand and use your other hand to peel down each section of the cup until you have a bare soil plug. Gently slide that into your perfectly sized hole and top dress the whole thing with 1/2” - 1” of soil and you’re done! It is a little late but I’ve never gotten any shock from doing it that way.
Hope this helps. Happy growing!