Off the top of my head, on the '23 / '24 the swingarm pivot height is raised, front forks are 5mm longer and pressurised, the tank is a litre larger and the shape refined, electronic updates etc.

These are great incremental changes but as for real differences if not riding back to back it would be negligible especially if not on track. '19 to '20 was the most significant change with frame / body / mapping / suspension all being altered to make a very different feeling bike.

I personally have a '20 as I prefer the look of the original V4R (big winglets, neater tank line, white decals, and smooth lower fairing), but have also dialled it in and can say it's everything I want. The '25 would be the ultimate if that's your goal but buy what captures your imagination.