If I bot a alt, while playing on a main account on like runelite legitly is there a chance they both get banned because of same computer thing or is it sep?
That's not true, if the residential ip is flagged that way jagex van fuck him up. My tip use a proxy on the bot alt
They "can", but they don't. I've literally never heard of someone getting banned for botting on one account when they only botted on other accounts on the same IP. I've been banned on dozens of throwaway accounts over the years, I've never been banned on my main or any of my side accounts I haven't botted. And I actually do bot sparingly on my main as well, and trade wealth directly between my main and sides. You're more likely to get your side account "flagged" for botting on a dirty proxy that literally thousands of accounts have been banned on before. But fair enough, this is all just opinions and personal experience. No one has "definite" answers.
