This Seeking Tech guide will show you a money farming spot early in Metaphor ReFantazio.
Use the following video as a reference:
Before you start, you should make sure that you have the Merchant Archetype equipped since it will give you extra money when defeating enemies in the overworld. You should also make that you are at least level 14.
Once you are ready, make your way to the Tradia Desert. There are a lot of weaker enemies here that will respawn when you go to Akademia or return to the entrance.
You should focus on taking out the three hyena mobs along with any crows or sandworms that may appear in front of your path.
After taking out the three hyena mobs, use the cat to go to Akademia to respawn the enemies. You can then defeat the three hyena mobs again before you return to the entrance to respawn more enemies.
I was able to get a little under 20K in around 2.5 minutes for every run.