Accuracy on CNC machines is a funny thing. The theoretical accuracy on the Low rider is very good (in the fractions of a mm), but it is dependent on how you use it. More specifically, how the toolpaths (CAM) are doing when cutting. If you want very high accuracy, you’ll want to do a finishing pass, where the machine goes through and cuts the pattern leaving a small amount of material, like 0.1mm and then does one final grazing with the bit to clean up the last 0.1mm and in that pass, there will be basically no load on the bit and it will be very very precise.
The other hard part is that the bigger the machine, the harder it is for it to stay rigid. If you double the length of an axis, you generally 1/4 the rigidity. Keeping your Z low and making it smaller than a full sheet size will help you a lot. Having a more rigid machine means the errors you can make in CAM can be a lot bigger and you’ll still achieve great results.
Engraving jobs like that are also dependent on having a consistent Z height. If you’re good at 3D printing, you can think of that as bed leveling. If you’re working on a small work piece, the size of a piece of paper, and engraving, the LR will do fine. If you want to carve a 4x8 sheet of plywood, you’ll probably have too much error in Z to do the whole thing in one go. If you’re through cutting a 4x8 sheet of plywood, you can just set the job to cut an extra 10mm deeper and it will just cut into the spoil board when it’s not at the right Z height.
All that said, I have carved plywood designs that were about 14" across and had good results, and my gantry is 60" wide. I have also cut out 24x36" or so pieces and they ended up better than I could do with a band saw and various sanding devices.
I will also say that I started with an MPCNC (the LR wasn’t a thing then) and then cannibalized it for parts for my LR. The MPCNC is very forgiving by comparison and it’s a great rookie CNC. The LR is OK and there’s a lot of tutorials and things on it. But it is more difficult than the MPCNC. Having a 24"x24" MPCNC for a year will teach you a lot, including how much you really want to have a full sheet CNC machine.