They are basically the same engine but scaled up. I’ve read issues regarding the 2.5, but I find it rare and does not seem that much of a big deal to fix to me. You cannot go wrong with either, Skyactiv-Gs are very reliable, but Skyactiv-Ds are a different story…
Those are just DTCs because of low/fluctuating voltage. They’ll go away after a few restarts. Get a new battery, OEM is crap