use mudfish, by far the best and cheapest vpn i've ever used, i have the same issue as yours, my ISP routes me through really bad routes that cause high latency, so i bypass that by using mudfish, it gives you wide variety of routes to connect to and pretty stable latency.
btw it's paid but it pays you for bandwidth not a subscription based vpn, and since gaming doesn't consume alot of bandwidth it's sooo cheap, i paid 5 bucks and i've been using it for a year or something.