Personally, for the ship of Theseus I have always leaned on the side of assuming it is the same ship. What's important to me is the continuity of it existing as a ship. A ship that was fully replaced through repairs while being a ship would still be a ship. However, if you fully disassembled a ship and then reassembled it, I'm not sure I could call that the same ship. Even if you used the exact same pieces, it would just be a similar looking ship. Especially if ship is used as a metaphor for life.

In the same way, I am fairly certain that me is the same me that has always been. Certainly I am a new me everyday, every new moment even, but the things that make me a new me are just small repairs and damage. So long as the... instance of me remains continuously running I feel like I'm the same me. Even if every bit of me gets replaced, and it does. Neurons in your brain will exist your entire life, but the molecules and atoms inside of them won't, constantly getting replaced.

I would never get in any form of actual teleporter. Hell fucking no, that is certain suicide. As for sponges, that is super interesting. At bare minimum that shows a level of sentience on an individual cell level that most people wouldn't believe. You should check out slime molds, another instance of globs of cells showing a strange level of intelligence.