Gym shark legging size questions

So I got gym shark legging back in 2018 and got them all size small, which fit, but it was small. I was around 155lbs then and wore a size 6 at lululemon. Now in 176lbs and I still wear size 6 for lululemon, but I am between medium and large legging for everything else, so for gym shark I know it’s better to size up (prevent see through and all that). That being said, for the sale I bought every pair of leggings they have all in size large and two pairs arrived today which were a little too big in my opinion.

Because of the sale, they have a no return policy but can do exchanges- the issue I have is that they don’t send the new pair out until the old ones make it back to their warehouse and right now the sale is even better. My other leggings won’t arrive until next Tuesday and will take days to make it back to the warehouse so what if 1) they’re sold out or 2) they’re no longer on sale?

Should I buy all the leggings in medium now and just have two sets of each, one medium and one large- that way I have comfier ones that if I ever gain weight, I can wear later, but also have tighter fitting ones for workouts at my current size? Money isn’t really an issue, but just want to know if it’s pointless to do this.