Hi. First congratulations on the best game since BG2, and possibly better even taking account for when it's made. Anyhow I understand it has not been decided if there will be DLCs and/or expansions for BG3. Personally I suggest you do the following:
Make DLCs with character options and Expansion(s) with game content. The DLCs would be fully optional, but I am confident there is a lot of loose money to be collected without projecting greed in any way - get paid for the job done.
For instance, I would pay a good penny to get my
Elven Accuracy feat and
Absorb Elements spell, both official supplements to 5E.
A meaningful way to do it would be to deliver one or more feat packages, spell packages and alternate class feature packages (the official 5e ones).
Beside that I guess we all hope for expansion(s) taking us to lv 20, and possibly beyond. I would be as bold as to say this game has the foundation to become a constantly evolving game adding more and more regions of Faerun, and even entirely new stories like classic d&d modules.
Just my two cents on the way forward!