As far as I remember, for that it’s better to use a vpn, but I don’t know if you can use both vpn and proxy at the same time since I also need a different IP.

What’s the problem with using both? If you need everything at once, maybe you don’t even need to choose? You can read more about proxies specifically in this article https://www.techmagazines.net/understanding-proxy-and-proxies-essential-tools-for-online-privacy-and-security/. Nowadays, many specialists, especially marketers, seo specialists, testers, can use both VPNs and proxies, even in combination with anti-detect browsers.