Red one - while your loyalty to Honda products - even those labelled HONDA, but made by some other company - is admirable, you are wearing blinders on this oil issue.
I have used a full synthetic gear oil (Castrol) in my ST1100 for over 20 years, as have many, many other 1100 and 1300 owners here and a full synthetic engine oil ( Belray and Amsoil ) for just as long. Zero issues.
You will never likely have a problem sticking with your Honda dino lubes, doing recommended change intervals, so you can consider yourself having done the right thing, in that sense. Probably paid a lot more for those HONDA products over the years too, but that is your choice.
However, one seemingly insignificant item on our bikes was what convinced me very early on that synthetics ARE superior to dino in wear protection - that little magnet inside the final drive drain bolt.
After two initial hypoid changes all those years ago, using Castrol dino, I noted the space where the magnet sits was thickly filled with the extremely fine metal particles that the gears had shed while working against each other. I switched to the Castrol synthetic hypoid and, upon inspection at the next oil change, that magnet was virtually clean and has remained so ever since. 'Proof in the pudding' of the increased wear protection, so to speak, for me.
Now, whether it would be of any benefit for you to switch to synthetics at this late date, having stuck with the HONDA dino all these 20+ years, is debatable. The wear patterns have been well established already, but for you to be arguing, basically, that dino, especially HONDA dino, is superior to any synthetic is just a load of rubbish.