Yes, Realme uses Realme UI, Oppo uses color OS and Vivo uses Funtouch OS. Funtouch OS is just a crap copy of iOS, Oppo's OS is good but not too smooth, and when my phone got the realmeUI update, not even whatsapp could be used properly, because they rolled out poorly optimised updates.
Oneplus uses oxygen OS which was earlier based on stock android, but now looks like copy of OneUI.
But there is a problem, in china, oneplus has started using oppo's OS in there phone. This trend has higher chances of to be followed in India.
These OEMs do give update for 2 years, but they usually slow the device. Oneplus also gives buggy updates sometimes, eventually leaving device in unusable state.
I have never seen any samsung user complaining about this, thats why i recline towards samsung. There is very less chance of a bug, but they atleast dont heavily slow down the device.
Although apple too slowdown the device through update, but it is not that much that even basic apps like whatsapp stop working properly. Also they do it timely, like after 4 years and not just after 9months(like in my case)
So yeah, Oxygen OS is better than whatever Realme/oppo/vivo give, but is going down the trend.
