Run the client in a browser like Brave or a fresh Chrome profile with no saved passwords or credit cards.
Some developers use Replit to host live versions of their hacked clients so you don't have to download anything. Eaglercraft Hacked Client Links Extra Quality
Rather than looking for "hacked" versions that may compromise security or violate server rules, players can focus on "Quality of Life" (QoL) improvements and legitimate client-side modifications. Run the client in a browser like Brave