You could begin with 'Heir to the Jedi' as it offers a fresh perspective and introduces some key elements. Also, it's not too overwhelming for new readers. But it really depends on your interests. If you're into specific characters or eras, there are targeted novels for that.
I'd suggest starting with 'Star Wars: A New Hope' novelization. It's a classic and sets the foundation for the universe.
Chapter 258, "Troops at the City Gates", is the clearest early answer because it pushes Knight Titan into a new phase or setting. The chapter gives readers a real answer by opening on Gu Hang and Wang Qi, this mother and son duo, discussed post-war... and ending on Through his military binoculars and the reports from his....
Chapter 361, ", Invading the Divine Realm", is the clearest early answer because Ge Wajia finally turns buildup into a real advancement. The chapter gives readers a real answer by opening on The Storm God Kingdom shook violently, and even Gu Hang in the real... and ending on Not to mention, the power of that incarnation was somehow used by....
Chapter 447, ", Iron Horse Naval Battle", is the clearest early answer because the buildup finally cashes out in a real clash. The setup is The small boat that had been following their trails didn't jump at..., but the pressure keeps building through It didn't matter if our boat was small, having many could do the job..
Chapter 409, ", Atonement Expedition, Independent Kingdom", is the clearest early answer because it turns Iron Armor Battle's situation into a concrete plot event. The setup is The grudge just keeps getting bigger., but the pressure keeps building through It had been some time since Cercis Flower was within the Princess.... Once the chapter lands on It wasn't about not being able to fight;
Chapter 821, "a major turning point", is the clearest early answer because it turns Ashen Dead's situation into a concrete plot event. The setup is Anconi Ben remained uneasy, but since things had come to this point,..., but the pressure keeps building through After all, from this assembly hall to the bridge command, it was at....
Chapter 255, ", The Liver and Gallbladder Fear the Cold", is the clearest early answer because it turns Luman Legion's situation into a concrete plot event. The chapter gives readers a real answer by opening on When Nes Luman and Gu Ming were so panicked that they didn't know... and ending on Their bombing target was the Luman Legion, which was interposed....
Chapter 338, ", A Hundred Thousand Favors", is the clearest early answer because it turns Rage Bear Legion's situation into a concrete plot event. The setup is These several changes directly reflected in the system conditions..., but the pressure keeps building through A few days ago, the option to annex finally appeared..
Chapter 428, ", I am the Dominant Bishop!", is the clearest early answer because it turns Warhound Titan's situation into a concrete plot event. The setup is In the span of over a year, she thrived on Jindi Star like a fish in..., but the pressure keeps building through The internal struggles within the Sect of Mechanics were quite....
Chapter 331, ", The Great Battle", is the clearest early answer because the buildup finally cashes out in a real clash. The chapter turns that into something concrete by moving from At the moment, this firepower proved immensely effective. to They could retreat no longer; they had to turn and fight.. What makes it stick is that the danger stops being abstract and the conflict around The Great Battle becomes immediate, forcing the surrounding cast to react under pressure.
Chapter 339, ", Fine Gold, Knight and Titan", is the clearest early answer because it turns Interstellar Warrior's situation into a concrete plot event. Early on, A thousand-tier draw, though not drained dry, left hardly anything.... By the end, It is a technology developed to compete with the Interstellar Warrior....