Motor Oil is one of those subjects where everyone has an opinion but very few people have any real knowledge to base it on. It's all "black magic".
After spending thousands of dollars and hundreds of hours doing oil testing in a taxi fleet plus, because I was curious I did for over 10 years with my own cars and motorcycles.
The biggest takeaway from all that testing was that the brand is the least important factor when it comes to selecting your oil. Every brand will have some oils that are suitable for your application and some that are not.
Provided you use the right grade (SG, SJ, JASO MA etc.) and the right viscosity range and change it within the manufacturers recommended intervals the overall life of the engine is going to vary by a small percentage (<3%) of km's at most. That was our result with taxi's ranging from new to 900,000km. We worked closely with a lab in Malaga WA and tested every suitable oil that was on the market in WA.
Contrary to popular belief there's almost no difference between car and bike oils. The contents are just about the same. The "friction modifier" in car oils that don't meet JASO MA is the only real difference. Otherwise, the additive pack used by the oil manufacturer will be mostly the same it will just be the percentages of the additives that vary.
Those additives come from only a handful of companies throughout the world, so the additives in Motul and Castrol and Amsoil and Penrite etc. came from the same maker, probably even the same batches. If the oil was bottled in Australia then the entire contents (including base-stock oil) was the same as others bottled in Australia. I assume the US and other countries is probably the same or similar.
The biggest benefits of synthetic oils are that you can run a longer service time interval if you're not using the bike much and it's ability to handle high heat (+125°C). If neither of these are a concern then you'll get the same from a semi-synthetic at a lower overall cost. We did find that mineral-only oils, though they contained many of the same additives because the base stock was of a lower quality would stop offering the same protection as the other oils much sooner. e.g. Mobil 1 was over 15,000km but the cheap mineral oil was done by 5,000km.
If you really want to know what's happening in your engine I really recommend getting your own oil tested. It's the only way to really know. The labs can tell you whether your oil is still protecting your engine. Large fleet users require this kind of information because it can save hundreds of thousands of dollars in maintenance and lifespan.