Your idea of putting down the plastic floor mat is a good one. Also, there are two different types of casters -- the most common casters on office chairs have hard nylon plastic rollers (designed to roll on carpets) which will leave marks, but there are also soft rubber rollers for hardwood floors. Check the link below. Here is a link that might be useful: Casters for Wood Floors

Laminate is pretty durable but it's far from being scratch-proof. If you take a wheeled chair, put it on any floor and have someone roll round on it, localized wear will occur. The chance of getting sand on the floor from worker's shoes is high. Wheels, especially plastic ones will become imbedded with abrasive sand. If you look closely, you'll notice that each time a caster wheel reverses direction, it spins around. It's literally just like taking sandpaper to a floor. I like your rug idea but watch out for sand filtering through and wearing the floor as the rug shifts slightly.

I work from home, and found that my office chair worked best on my Karastan rugs when I bought a clear chair mat for it to glide on. It also protects the rug. Here are some examples on Amazon - Carpet chair mats

Wow, so excited to see such good and varied inputs on my request! Thanks @Flo Mangan - I am now certainly going for a ladder shelf for the corner. I am not sure of moving the desk away from its existing place for precisely the reasons @functionthenlook mentioned - my desk job can sometimes result in 8-9 hours, and I do plenty of video calls throughout the day. So not only is it nice for me to have a view (which BTW Flo is right, it is limited since the windows are a bit above my eye level (photo of the view below)) but it is also pleasant to have light on my face. Further, the remaining space in the room comes in handy when the occasional extra guests stay over and the sofa beds need to be pulled out. Thanks everyone for all the rug options - this weekend is going to be (window) shopping weekend :)