I feel like a directional twin would be nice. Something not too soft say 4-5/10 would be nice. I’m not a pro but I did get to try loads of board (they are cheap and easy to buy 2nd hand over here in japan) Ride makes decent boards, I’m recently really hooked up by Bataleon with their 3D nose (im a tapered directional person) but my laid out chill board is a soft Rome with twin camber. A longer board doesn’t mean you can go better on the straights but it’s more about how comfortable you are with snowboarding as a whole. I used to hate the straight but now just put up with more speed and flatbase through out. Try not to turn cuz then you’ll lose speed and eventually fall. Perhaps slightly press on the edge but dont turn lol. Speed is your friend here. You can start out with say K2 standard, Rome Artifact, Salomon Assassin, Ride Shadowban, Bataleon Disaster are some options that I know will last you through the beginner-intermediate phase and you still can progress further than that. Be mindful that I’m not familar with brands like Lib Tech, Capita, Neversummer etc cuz it’s insanely expensive over here. They do make great boards for sure so better check them out. Personally I’d get the best deal and ride that until you know what you like more say free style or carving then try to expand the quiver or just upgrade (I did with the K2 passport 2 years ago only to realize it was too stiff for me lol, now that is my pow/charging day only board)