Prefer 4G over residential proxies, but if you're using them for burner accounts, datacenter proxies are also suitable as the choice between them doesn't make a significant difference.
Using a 5-to-4g proxy is an effective choice. While some people recommend using rotating 4g proxies, I believe it is better to employ a static 4g proxy. This is because Instagram (IG) has the capability to identify rapid IP changes and may raise a red flag on your account. Personally, I have encountered no issues while operating five accounts on a single 4g IP. However, the outcome may vary based on the specific actions performed on each account.