You can try enabling
Track>Free item positioning.
It's easiest if you set the track to this before you record all the takes (because Reaper will then auto-size all the takes to fit), but you can set free item positioning afterwards and then right-click on the item with all the takes and select
Takes>Explode all takes (in place). You probably will have to resize the items to not overlap so you can see what you are doing, but it's easily done by grabbing the small boxes at the bottom center in every item.
When all of your takes are exploded to separate items on the track you can edit them individually without affecting the other takes/items.
*I'm selecting 'Explode all takes (in place)' outside of the frame