Greetings!
I write to tap into the vast experience of Wazua folk - it the current status of COVID-19 which has seen MAJOR distabilization in the real estate sector, which would be a safer bet in terms of capital investment; residential or commercial/retail?

The place is on the Northern Bypass road githogoro/runda environs next to Astrol Petrol station

I would go mixed use. Commercial for the first two floors and residential for the upper ones. You are in fact in a sweet spot, right on a major artery. Tenants (both comm and res) will be calling your phone hard and heavy to get space.

I would be hesitant to develop land in the middle of a slum. Capital appreciation, a major component of return from real estate is limited.

As I said on Jon Jones thread where he asked about building a block of flats, listen to Wazoo naysayers at your own peril. Your land is very prime my broda, as you have pointed out, nothing is static, especially when all these bypasses and new highways are being built. Kangemi is also a slum but wait until Waiyaki way expansion is complete. Ask even at present how much an 1/8th is going there already. Build a mixed use..best of both worlds..you can never go wrong especially in such a prime location. My humble two cents. Good luck and WHEN (not if) you succeed, kindly update us!