I've been private messaging the OP back and forth quite a bit on this very issue; Delo Ultra Gold 15W-40 was my recommendation based on a number of factors.
What a lot of people, especially those who haven't lived in this part of the world, fail to realize is we have a major problem with super fine particles of sand, which eventually make it into the engine no matter what you do. Use the best air filter in the world without sacrificing flow, and you will still find dusty particles of sand in your zip tube.
The best way to get around it would be to use an oil bath air cleaner setup, similar to Mercedes-Benz diesels a couple of decades ago. But it will require quite a bit of work to put together; bearing in mind most fabricators in this part of the world don't go to trade school - "Watch and Learn" is how they master their "craft" and even then, finding someone passionate, who thinks creatively outside the box, to fabricate something like this for you out of the right material is about as common as hen's teeth. If you pay peanuts, you get monkeys and that's exactly the situation in many third world nations; the passion just isn't there and neither is the drive. Then there's the issue of warranty with the OP living in a country where the Magnuson–Moss Warranty Act is unheard of and does not apply. If his passenger side front wheel bearing were to fail, the dealer will use the oil bath setup as an excuse to deny his claim. Good luck finding another Toyota dealer, because out here it's a monopoly.
Then there's the issue of oil formulation. The Shell Rimula R6 M is currently only available in 10W-40 flavor, and blended in Oman. What's in the jug will be something quite different than what's in a jug of Rimula R6 M somewhere like the UK. About a decade ago, Liqui-Moly had a project in the Middle East where they analyzed local blends of popular brands, such as Castrol, Mobil and Shell, comparing them to what's available in Europe. Most products blended in the Middle East didn't even meet the specifications printed on the bottle; for example an MB Sheet 229.5 "approved" oil had a NOACK of 15% and a calcium content of 4,000 ppm with barely much of anything else in the additive package.
Chevron is one of the handful of exceptions to the rule, because their quality control is that good in this part of the world. The Government of Dubai has picked it as their lubricant of choice to maintain much of their equipment, and Dubai Ports World, a private enterprise, also worked exclusively with Chevron to maintain their machinery with pretty decent results.
Long story short; oil is cheap, engines are not. For a fleet, UOA would make perfect sense, since factors such as downtime affect profitability. But for an individual, particularly someone living in a country where oil analysis facilities are not common, reducing drain intervals makes more sense. You can't just order a free sampling kit from Blackstone here, and mail it off once you get a sample. Factor in the boneheads running dealerships, who not only do not have the proper technical knowledge to understand an oil analysis report, but will give the OP hell for extended drain intervals because "Toyota doesn't recommend it", ultimately denying warranty on a $70,000 vehicle, and you get the idea. Even if you were to ship oil samples for analysis, good luck explaining the package is safe to the boneheads at FedEx, DHL, UPS, etc. as well as the local aviation authorities, who are not as understanding or flexible as those in the U.S. Ask me how I know; been there, done that and got the T shirt. Unless there is an underlying engine problem that oil analysis could help with, it's just not worth the hassle for an individual in this neck of the woods. If the OP wants to go through with it, that's his personal choice. But in the part of the world, and for me personally, the KISS principle applies.