Yes rental are only good if you want to park the money.
10yr treasury bond of 10 million can give you 1.2m each year - 15m - can give you 1.5M - or almost 120K per month. So it better to invest in those infrastructure bonds. Zero overheads. Zero headache with tenants. Most are tax free. You get paid every six or 1yr for 10yrs.
Agree on warehouse - and commercial building - rather than residential rental. Commercial building will earn you more - you dont have to provide toilets and name it in every unit.
Agree on providing water - and such services
Seasonal crops - unless you're quiting your job - that like raising cattle or chicken - or tea - time requirement!!
Best bet - plant permanent low maintenance crops that you harvest for three months every year - that you can take leave and manage the harvesting - then go back to your day job
Of course high maturing trees are the best - zero maintanance - great returns.
All in all - first nail your day to day - either in job or business - that can give you money to live day to day comfortably.
Only then - can you start investing.
Rentals are very good investment for stolen money,retirmement or inheritance because they are capital intensive.Buy a in Nairobi maybe Rudi for 5MN,Build 6 2BR units for 10MN That is 15MN already..Hire them at 15K monthly each with 50% occupancy monthly income is 45 k..it would take 30 years to get ROI..I think I'd rather build a godown for 3MN..Hire it for 50K monthly to SMEs like bakery or processors..sink a borehole next to it and have two water bowser that which would give 100k net monthly.
As for seasonal crops,As long as you are doing drought resistant grains and cereals.you are good to go.The rule is very simple.
1) Own the land
2) Have a water pan/borehole..harvest WATER.
3) own trucks to transport to market.
4) Process.
There will soon be oversupply of avocado.Id rather do mangoes oranges bananas.