28 year beginner - learned snowboarding recently, now want to start skateboarding and learn freestyle tricks

Hey folks, I'm 28 and thinking about starting skateboarding. I recently learned snowboarding and really enjoyed it, and I also learnd Decathlon waveboard in thisJanuary, so I'm somewhat comfortable with balance.

Now I'm planning to buy my first skateboard and want to start learning freestyle tricks like manuals, shove-its, and ollies.

For reference, I'm 175 cm and 74 kg.

What deck size would you recommend for someone my size? Also, should I start with a complete skateboard or build one myself?

Any beginner tips or brand suggestions would be appreciated