Some comments on the "R" in R&D.
When I worked at a consumer products company (beverages) our research and development functions were practically combined. One person led both research and development. There's not a lot of research going on in a beverage company compared to other industries.
But when I got into the Pharma industry, I saw that Research was a totally separate function from Development. There are 100's of ideas and projects in Research and many of them never see the light of day but once a project meets the Proof of Concept goals and is deemed marketable, it passes onto Development to figure out how to engineer, manufacture and in some cases how to market it.
We have much visibility into Tesla's Development pipeline (Gen 2, Optimus, Robotaxi, FSD, even the Tesla van is likely in Development) but we have no visibility into it's Research projects. Likely years ago, Tesla began research work on Steer by Wire, Vehicle to load charging, 48V, single casting, etc. but we were mostly oblivious to it until these ideas moved into Development or were delivered with a product.
At the pharma company I worked at, all analysts covering our stock knew our drug Development Pipeline well but none knew about our Research projects.
My point here is that there are many exciting projects that the Tesla Research team is working on that we won't know about until a few years from now. There will more positive surprises that will move the companies valuation forward.
Elon has said that Tesla doesn't do pure research. That is, any kind of research is expected to be delivered in a product. So all research is done with an eye toward profitability. This is a different mindset from companies that do a lot of research and then look to see if any of them can be productized.
I'm not sure how much secret research is really going on at Tesla. To take Optimus as an example, it sounds to me like Elon talked it over with some people and came up with initial specs for what it should be. But it sounds like engineers didn't take out their screwdrives and start working on a prototype until shortly before the announcement on AI day. (Correct me if I'm wrong)
Are there some big secret projects that Tesla is doing actual research on? That's very hard to say. But I kind of doubt that there is anything going on now that we won't hear about for several years. Tesla tends to have shorter time frames between idea and announcement.