Does it really help if I use incognito mode in my browser?
Not really. The only thing that incognito mode does is forcing browser not to save anything that you are doing at the moment (cookies, history etc.) beside downloaded files, of course. Your ISP can still identify you and see what you are browsing. Try Tor browser, it might be slow but that's because of how it works.
I think VPN with no logs should work better. Either way, ISP will know that you are using VPN or Tor browser. Well, if you use bridge in Tor then it will be hard for ISP to know that you are using Tor. The reason VPN is better most of the times is that VPN is faster. Or if you need total anonymity, you can use Tor via VPN.