Is it cheating? Yes. But so is cloning MissingNo. In a single-player game, the goal is your enjoyment.
(dialogue, menus, etc.) rather than your personal save data, you should look into ROM hacking tools instead: PKHeX Guide For Nuzlocking/RomHacks | Save Editing Tool pokemon fire red save editor
But then, there are the "what ifs." The save editor allows you to play god with the narrative. You can edit your Trainer ID, change your rival’s name, and modify your wallet to have maximum PokéDollars. Some players use it to craft "challenge runs"—giving themselves a team of six Magikarp at the start of the game to see if they can survive, or editing in a full team of level 100 legendaries to bulldoze through the Elite Four for stress relief. Is it cheating