You’re right, it should work with 6 - I plucked 8 out of the air just because at 100W per panel, a low number of panels won’t be making much use of the 2000W capacity of the eco flow. Nevertheless, yes, it should be working.
What do you see happening with the ecoflow? Are you getting no charging at all, or just less power than you expected? If you post up more details of what’s going on I’m sure you’ll get more engagement. People around here are generally helpful.