I am waiting for the datamine honestly to figure out what I want as I don't care or want to be surprised. I will probably once again be doing rotation like I've done for the last few games and catch more than 6 and use. But for now...
Scourbunny.
Corviknight
Yamper
Galarian Ponyta
Scorbunny will probably remain my top pick as a starter, as I don't really care about the other two. I've been in love with Corviknight since I saw it. I assume it is the regional bird for Galar, so it will probably have earlier stages. Yamper will depend on Scorbunny's typing when it is fully evolved, though I may still use it. Galarian Ponyta is almost a hands down choice as I don't like many psychic types.
When I play games, I only use new pokemon. I try to avoid using old pokemon until after I beat the game. When I use a rotation format, I usually will switch between 10 to 12 different pokemon. The exception is Alolan or Galarian forms as I consider those new pokemon because they have different looks and different types that are permanent.