50 IG Username changes requires a proxy?

I want to buy 50 IG accounts AND change username on each of them from the same IP/Machine.
Would it be SAFE for these accounts not to get banned (I am not creating them) OR I need to change a dedicated proxy every 3 accounts just to change the username?

You'd want to change their usernames on separate proxies. Instagram would see you have access to 50 accounts on the same IP and that'd be a red flag.

FollowLiker has this feature that can be done without automatically logging in/out of every account, and I'm sure MassPlanner does too.

If you don't have any of these softwares, then I'd recommend doing it on a data plan (4G) and not on wifi... but that's still risky. I think the standard rule is trying not to log into more than 15 accounts on the same device.

you can using mobile phone for change username and dont using wifi, using mobile 3G/4G its safe... every 5 account you turn off your signal and turn on to change your ip