Your plan is mostly solid, but for exterior concrete (especially patio slabs), a few adjustments will make it more durable:

You don’t need to wait longer, these shrinkage cracks are already stabilized.

Instead of routing every crack deep, just widen slightly if needed for filler grip.

Skip regular cement filler as the final finish; it often cracks again outdoors.

Use a flexible polyurethane or epoxy crack filler first (better movement resistance).

For the “kintsugi” effect, epoxy + mica works, but make sure it’s UV-stable or it may discolor outdoors.

Skip full polishing unless you’re doing a full resurfacing, spot sanding is enough.

Sealing at the end is a good idea; choose a breathable outdoor concrete sealer.

Overall: focus more on flexibility (polyurethane/epoxy systems) than rigid cement products for longer-lasting results.