Convoluted possible way to root past 5.x update?

[Pyro3138]

Ahoy there, fellow Android users!
I've been dealing with my S5 Active getting slower and slower as the days go by, leading to frustrating lockouts and apps coming to a crawl, with my available RAM seeing a 75% consumption while no apps are open in the background. Tonight I figured I would finally put my foot down about this and do research on how to root this device. Unfortunately, everywhere I go says the same thing. "Past 5.x update, you're screwed."

But this soldier isn't taking no for an answer. And this is where my curiosity peaked on possible ways to get around this.
Would a complete factory reset of my phone bump the kernel down to the earlier 4.x build? If yes, I believe I'd then be able to go the normal route of rooting this bloatware-in-handset-form brick.

Any tips tricks and pointers would be highly appreciated; I can't stand dealing with this slug of a phone any longer, and I feel wronged as a customer to be stuck in such a crap situation of having the bootloader locked.

 

[B. Diddy]

Welcome to Android Central! Have you already tried a cache partition wipe? https://support.t-mobile.com/docs/DOC-28492

 

[Dawn Hnatishion]

They do that deliberately because they can't stand people who don't buy new phones every year and want to keep the phones they have because of all the money you already have invested. It's a rip off that they no longer offer updates for older phones.

 

[Shuck Ducky]

Absolutely true. They hate it when the jig is up.