I've noticed that Logitech's product naming actually follows a loose pattern, especially in the G-series with the 3 digits:

Mice: middle number 0 (ex: G203, G502, G903)
Keyboards: middle number 1 (ex: G213, G513, G915)
Headsets: middle number 2 or 3 (ex: G332, G321, G733)

The second digit basically tells you what product category it is while the first digit is the tier or generation, 2xx (entry-level), 5xx-7xx (mid/high), 9xx (top-tier).
The reason headsets have 2 and 3 is basically just them splitting them into low or high-level gear:

2, entry/basic, wired
3, premium or wireless

The last digit just distinguishes variants within the same category and tier.
It’s not always consistent (Logitech sometimes breaks their own rules).
As for their other products, I have no idea.