CoconutTrebuchet First of all, for your first post on the forum or Discord as far as I'm aware, your shipbuilding skills are already pretty much competitive-level, at least when it comes to logistics without crew assignment.
Building advice:
1. Probably the most important improvement you could make is switching the layout from being heavily central to more spread out. The main reason for this is railfans. At the moment a railfan will be able to one-shot both reactors due to their placement in a line. A good idea is to add layers of armor in front of your reactors to absorb burst damage from things like rails.
2. Another important thing to note is that going for one or two weapon types is usually better than "all of them". In the current multiplayer scene, I'd focus on heavy lasers, EB, and flak for a few reasons. The main reason is the prevalence of missile orbiters. Cannons can't hit them and lots of flak are required to nullify their missiles. Modern orbiter/ultralight walls use 8-12 flak and can reach speeds of around 120 m/s for catching and killing missile orbiters.
3. The layout. As I said in the first point, the layout should probably be changed to increase its effectiveness against railfans. Currently the popular layout uses 3 large reactors which each power their own "modules" with lasers, engine blocks, and shields. This means that if one of the modules gets destroyed the other two can still function, and are usually enough to get to the side of and kill a railfan. I highly recommend joining the Excelsior Discord server to see examples of what I mean (and to more easily converse).
4. I see you're already heavily focusing on forward thrust, and I actually suggest focusing on it more. With the current layout you have thruster modules dedicated to reverse and strafe thrust, which you won't usually find yourself needing. Also, small thrusters should not be used on ships above around 100k as they get less of a boost from engine rooms than larger thrusters and are a less space-efficient. Other than that, good job powering your engine rooms directly from walkways and putting all your thrust around them.
5. Use crew management. While it seems daunting and not entirely necessary I assure you it's worth your time. I have a guide on it which should break it down well.
Piloting advice:
Against ships with turret weapons you want to maintain an orbit around them and shoot down their shots with your flak. Ideally you will also have some of your flak able to attack along with your other weapons. Try not to ram cannon, rail, or ion ships head-on, and if you're about to get rammed use the bump it gives you (and boost if you have them) to try to spin out of it.
Against railfans, you want to minimize the time they have to shoot at you. So, charge at them with a slight angle so only one side of your wall hits them on the front and you "pivot" to their side. Then activate your boost and ram them on the side/rear and slowly eat through the armor till they die. Using this pivot you should only really lose one of your reactors in a worst-case scenario.
Against railtraps, you also want to ram their sides, but you have the extra task of keeping the other trap behind the one you're ramming so they'd have to friendly-fire to hurt you. This is pretty inconsistent even with great piloting and is why railtraps are probably the best counter to walls at the moment.
Against missile orbiters, you want to be very aggressive. They'll win by slowly getting missiles around your flak, so killing them quickly, even if it seems risky sometimes, is better overall. The main strategy for beating missile orbiters is kind of similar to railfans, you want to intercept them in their orbit and pivot off their front or side till you are faced with their rear of missiles, then boost and take them all out and win. This is where lasers are a lot better than cannons, which have an extremely hard time hitting, also flak does very well because it's hitscan.
Overall, your ship is better than a lot of peoples I've seen posted here or on the main discord in the past. Keep on improving and you'll be doing well in multiplayer elim before you know it!