Im beginning to learn BJJ. The gym I am attending teaches both gi and no-gi variants on different days of the week. I want to attend as much as possible, and I was wondering if there is any disadvantage for me to attempt to learn both variants at once. Or is one better to be picked up after mastery of the first.
Short answer to your question: There is no disadvantage to learning both variants at once. And now for some detail...
Training as much as possible is ideal. If that means doing both gi and nogi, so be it. Doing BJJ, regardless of what you're wearing, will make you better at BJJ.
Beyond that, it depends what your goals are. In the months leading up to an MMA fight I train much more nogi. I don't want to cheat with gi grips when those won't be available in a fight. If I'm doing a gi BJJ tournament, I'll train more gi. If I have nothing coming up, I'll do both equally, or whatever I feel like more. If you have goals to fight some day I would avoid relying heavily on gi techniques. The gi can breed some bad habits, and make you rely on techniques that aren't possible without the gi. Learn everything, but be aware of what techniques you're falling back on in times of adversity.
Neither style is "more technical." Grips are king in gi. Underhooks are king in nogi. Just because nogi tends to move more quickly does not mean it is less technical. Latching on to a grip in nogi is often not enough to secure a technique. The lockdown from half guard, underhooks (top or bottom) in half guard, side control, and butterfly guard are essential. Yes, the scramble becomes more important in nogi because of how fleeting positions can be, but there are effective techniques even within the scramble. To the untrained eye it may appear frantic, but a trained nogi grappler or wrestler's technical execution in the scramble often is the difference between a win and a loss in a tournament match.
Point being: Train for what you want to do. Train for your goals. If you're training to get better at grappling, do whatever your gym is offering, whenever they offer it. More is better. If you're just training for fun, do whichever is more fun!
Basically you have traditional (Gi) vs. every day (No-Gi). It really depends on what you want to learn. There is something said for learning the traditional and perfecting your technique from that setting and then adapting to every day use. Can you learn them at the same time? probably, but you will need to be sure you approach each with that in mind and don't mix one with the other, but commit to learn each one in the way it's instructed. This will help you gain mastery over both and be able to adapt as needed.
I would ask the instructor for sure though as there may be a specific process to their training that it would benefit you to start with one before the other in order to ensure proper techniques are learned. Usually the traditional is the starting place and sometimes moving to the non-traditional too soon can cause bad techniques to be learned...which unlearning/re-learning is always harder than learning right the first time.