I can guarantee you that in Sky Dolly you can seek back and forth as quickly and as often as you want, you won’t corrupt the replay data (which is stored in an SQLite database, also known as the “logbook”).
However depending on much scenery data and objects need to be loaded in - and at “what timing” - you may crash the flight simulator. Happened to me a couple of times in the past when I was seeking “to the very end of a longer flight”. In such a case simply reload the flight simulator and continue the replay. Again, your actual replay data won’t be affected by this, it is safely stored in the “logbook” (and not modified at all during replay).