It’s been a few years since my own AMS-NBO flight, but my recollection is that it wasn’t bad. A 767 IIRC. At the time, the NBO airport had just burned and so customs was conducted by a large unformed man sitting at a card table.
Customs was the biggest pain. Only Euros, Sterling or USD, cash...bills must be crisp and less than 5 years old. And there was no ATM available if you didn’t have cash. Passengers were loaning each other cash to pay the $60, with the promise that there were ATMs after customs. Hopefully the ATM situation is resolved now. I distinctly remember the card table piled over a foot deep in crisp $20s and $100s. Not even a box to put it in...just a huge pile of cash. I bet the crisp, new bill policy remains in effect however. So remember that bit.
That said, my fondest memories are of the Kenyan passengers. All remained seated until their group was called to board, and were polite and orderly during boarding. Even on my return flight AMS-ATL, about half the pax were Kenyan. Boarding at AMS was amazingly orderly. The only gate lice were American and European.