The images look worse than expected

Quality is a compression setting, not a resolution setting, and the default sits deliberately below maximum because the file-size saving between there and 100 is large while the visible difference is small. If artefacts are visible on your product photography, raise the quality and re-run; the originals are still available to restore from, so you can compare directly. If detail rather than compression is the problem, your maximum dimension is doing the work, so raise that instead.