If you have a lot and I mean a lot of money, then you can use 4g proxies for many Instagram accounts. In theory it says that if the number of accounts you manage goes above 10, it does not make sense to use 4g proxies anymore, as they're just too expensive.
You could go for residential proxies (datacenter proxies won't work with Instagram, don't even bother), they will be cheaper, but still expensive. As I've said, if you don't have the budget, maybe you should rethink your Instagram strategy?