i.m not reading that all

Saying "don't play multiplayer" on a client launcher designed specifically for multiplayer makes no sense. You didn't get "hacked," nor is your PC or account in any danger.

What actually happened to you:

• Old Roblox clients do not have FilteringEnabled: This means the host of the server (or anyone with execution privileges) has total control over what happens inside the game. They can change your player name, modify the leaderboard, show custom text on your screen, or change the environment using simple scripts.

• Novetus clients have security patches: While having patches doesn't mean it's 100% impossible to use exploits, Novetus clients have many security fixes and is not that insecure as you think. Old Roblox exploits from 2007–2012 doesn't work in Novetus because the developers patched those old vulnerabilities. I've personally tested old scripts/exploits from those clients in Novetus and they were completely blocked.
• IP grabbing is extremely rare: You shouldn't worry about someone grabbing your IP or hacking you. The vast majority of "exploiters" are just script kiddies downloading a basic .exe or injecting a .dll to mess around with Lua scripts; almost none of them have the knowledge to trace or extract IPs. The probability of running into someone who can actually do that is extremely low.

The real solution:

• Host your own server: If you want a safe experience, host the game yourself and only share your IP/port with trusted friends or family.
• Play on trusted servers: If you join public servers from internet, only join established communities that run anti-exploit scripts or active moderation.

Just because someone changed your name in-game, you immediately think you're in danger, that they're going to grab your IP, and steal your accounts or whatever. Joining a random public server and seeing scripted text on your screen isn't a security breach, it's just how Old Roblox engines work.