I feel you, the first time I played, the team I had planned had Overqwil, Annihilape and Galarian Weezing, only to find out I couldn't get them until the DLC so I got stuck with Jothonian Qwilfish, Primeape and Kantonian Weezing for most of my run. 😅
To transform your Pokémon into their regional forms and to evolve Pokémon like Dunsparce, Primeape or Girafarig you need a Sacred Stone, only available after completing the Jotho arc. When you do, if you want to get them faster, after Giovanni assigns you three missions, start with the one that takes you west of Cianwood, you can get two Sacred Stones there.
Also, the first time I played, you only get one Rocket Stone to get Rocket evolutions. I don't know if that has been changed but choose wisely.