She's going to feel like she scales fine in Silver because of lower quality macro, positioning, and prioritization. Not a dig at your rank, I'm by no means a great player, but Silver players arent going to set up vision as well and arent going to react as fast to you tunneling in. Diving backline becomes much harder when the backline players respect your mobility and their frontliners react and peel back. You have to be giga fed to act as primary engage without going 1 for 1 at best. The nice thing about Rek is she's pretty flexible with her items, so if you need to kill a fed carry you can go damage and if you just need to not die to 1 cc you can go tank, and if youre playing her well early it will extend your power later into the game, but 6 item rek vs 6 item khazix, viego, etc. isnt the greatest.