I’m not from the Dorico team, but as a user and a reader of this forum for quite some time now, I think I can answer your question (and free some seconds to the team — I’d rather have them spend their free time in spending quality time with their families and friends, so that they can keep up their good work when they have to ^^).
Tabulation is part of the scheme (and main part IIRC) of Dorico 3. You should not expect those to come “soon”, and anyway the team never gives precise dates about new features because they notice how complicated it is to implement them when they are doing the job. We are now expecting Dorico 2.2 (probaby in the next four weeks), and this is supposed to be the last free update. Nevertheless I would not expect tab notation to come into Dorico in the next six months, but this is only guessing from my part. I might be wrong, but my understanding was that the team wants to achieve a very complicated (and highly useful) reduction function, before they tackle tab notation.
The only thing we are quite confident about, is that when tab notation is implemented in Dorico, it will be top-class notation. This is the standard they’ve accustomed us to.
Again, sorry to reply here while I’m not in the secret of the Gods — if I were, I could not answer your question at all !!!