I started looking into non-carplay/auto big-screen head units when I bought mine, and kinda hit a wall on it.
They're either really old, and windows CE, or shitty android based ones from alibaba.
As much as I hate putting myself into a system that depends on my phone, I don't hate androidauto/carplay based systems. They just kinda...work.
If you just want a basic head unit (single din), the name brands are, honestly, much of a muchness.
They all use very similar 4x50w (iirc, 22w rms) output amplifiers.
The only real options are number of pre-outs (for connecting subwoofers, or other amplifiers), and whether or not it has a CD drive.
It amazes me that I was allowed to pass my test in a micra, then be fully qualified to drive everything up to a LWB van, or a range rover.
I found a right hand mirror on my bike sticking out actually did a lot to give me more space.
Someone I know fitted a big (plastic) spiky looking thing at the end of a handlebar, which served the same purpose.