I currently own an 8+, an XS Max and an 11 Pro Max. I can tell you from experience that they are all excellent and useful devices, though some might say the 8+ is getting long in the tooth by now. I wouldn't hesitate to recommend the XS Max if the cost of an iPhone 11 is an issue; the Max has a wonderful screen and a superb camera. The XS Max is also quite powerful and it should be useful for several years to come.
If you have the money, go for the iPhone 11. But I think you'll find the phone itself is only incrementally superior to the XS Max. The camera on the 11 Pro Max is wonderful but whether it's worth the extra money is a decision only you can make. Definitely go to Best Buy or an Apple Store and try them out.