Generating OSM png tiles for offline use

I'm very new and very confused about how to accomplish a seemingly simple task: generate my own OSM .png tiles for offline use. Since I want to be able to have a huge amount of tiles, I don't want to load the server by downloading tiles directly from tile.openstreetmap.org.

I was using Creating your own tiles, but learned that this method is outdated with the new styling method: mapnik-stylesheets issue #15

Since this is all new to me, I'm quite confused at the sheer number of methods and tools I've seen recommended to download, format, and render OSM tiles. As far as my progress, here are the steps I have taken:

1. Created a Postgres database named gis, enabling the postgis and hstore extensions
2. Downloaded arizona-latest.osm.pbf from https://download.geofabrik.de/north-america.html
3. Used osm2pgsql to import arizona-latest.osm.pbf into the Postgres database gis: osm2pgsql -G --hstore --style openstreetmap-carto.style --tag-transform-script openstreetmap-carto.lua -d gis --slim --flat-nodes /home/user/nodes.cache --cache 5000 /home/user/downloads/arizona-latest.osm.pbf
4. Generated shapefiles using scripts/get-shapefiles.py in the openstreetmap-carto directory
5. Created osm.xml by running carto project.mml > osm.xml
6. Successfully generated an image using generate_image.py from the outdated mapnik-stylesheets with warnings about failing to understand the new carto xml format.
7. Failed to generate tiles using generate_tiles.py from the outdated mapnik-stylesheets with the same errors from generate_image.py.

I'm at a loss at where to go from here with my current understanding of how this all works. If anyone can point me in the right direction, I'd greatly appreciate it.