If you want more Amber, then the Sign of the Unicorn (1975) by Roger Zelazny gives you exactly that. Corwin is now regent of Amber, for all the good that does him. Amber is so full of issues that rulership is a form of self-inflicted punishment. It's here that the politicking gets worse, and the complexity of the backstory emerges.
Roger takes time to do some very clever retconning in this book. He takes the challenge of going over his previous work, finding the inconsistencies and dropped plot lines, twisting them about, and turning them into a feature. When Amber and all its children get complicated, they get very complicated. They got twisted enough that I didn't quite follow all the twists and turns, let along spot any of the plot holes. For the most part, the entire point of the book is to retcon, to smash more plot points into the road accident that is the story arc, and leave you wondering how anyone could walk out alive.
If you are looking for "quality" writing, this isn't it. We continue living on the business end of a hack writer with a typewriter. That doesn't mean that the subject matter isn't compelling, if you find such matter compelling, but if you aren't entertained by the matter, the prose will have nothing else to entertain you with. There are often logical jumps between chapters, with some chapters having almost no explanation behind them and no orientation within them. There are some twists which feel random, not more complicated than "hey, let's go over there."
In my youth, I thought it was my fault that I didn't quite follow some parts of this book. No longer do I think that. Even as an adult, I wonder at the nearly arbitrary advancement of the plot and the swirling mixed colors that constitute a plot. I'm reading this series straight through and I still find myself alternately lost, thrown, and bored.
If you love Amber, this continues being the series for you, but if you don't, this book will surely be the rocks that you crash upon.