2.4 GHz band - Wi-Fi routers - question?

We have 17 wireless devices. We have (2) 2.4 GHz band - Wi-Fi routers.

Each of these 2.4 GHz band - Wi-Fi router can handle up to 20 wireless devices.

Question:

Should I connect all 17 wireless devices to 1 router?

Or

Should I connect 8 wireless devices to 1 router and other 9 wireless devices to second router?

Remember 2 routers only have 2.4 GHz band. No 5 GHz.

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