Hi. First off Tesla is not just an EV company but more of software company that manifests in automobiles. This distinction is important in that while most traditional automobiles devalue due to age, Tesla cars improve with added functionality through regular software updates. Musk never intended Tesla to grow to the size of GM and gave the EV design to other auto companies in the hopes of rapid adoption of the EV technology. With that said, as a Tesla stock owner who has benefitted quite well from starting with a small position in 2009 and has grown ones shares through stock splits etc, I would sell no more than 1/2 my position and retain the other half. No one has a crystal ball so managing the upsides as well as the downsides are built into this strategy. If Tesla continues to do well, well then you have 1/2 the position to play with. If the stock continues to decline, then you have taken profits before experiencing this risk. This strategy has served me well over the years as I am now fully retired and manage my own portfolio.
I myself am huge fan of Mr. Musk and knowing what success he has had with Tesla, SpaceX as well as Project Omega (generative AI), I plan on sticking with him. Good luck.