You can, but the question is why would you want to. Trying to use 20+ year old technology as a "modern" desktop is going to be an exercise in frustration. Web browsing especially is going to be slow and incompatible with many sites. NetSurf is an amazing piece of AmigaOS 3.x programming, but it's not comparable to Firefox, Chrome etc. running on even a modest PC. The Amiga is a "retro" computer, not a daily driver. Although many use them on a daily basis for fun and nostalgia, most people also have a PC or Mac for getting actual work done.

If you really want a modern desktop experience that isn't Windows, Linux or macOS, I'd suggest:
-An AROS box - can be built cheaply out of old PC components as long as you choose them carefully
-MorphOS on a fast PPC Mac, or the upcoming X5000 version
-AmigaOS 4.1 on the X5000 or upcoming A1222

Those options are still going to be somewhat limited and frustrating due to the lack of software, but the hardware is at least up to the task.

Or just build a Linux box. As someone mentioned before, LXDE, XFCE, Mate etc. are lightweight, almost Amiga-like desktop environments. Distros like Ubuntu and Mint are very easy to install, only requiring you to occasionally edit config files (no harder than editing your startup-sequence on an Amiga).

Or just VNC into a Linux(Windows if you prefer) box from the Amiga if I need a modern web browser... For most things iBrowse or netsurf works well enough for my needs.

I use my CD32 + Riser + TF328 (8MB + IDE) + IDE->CF + 8GB CF + PS2 Keyboard for retro real feel, WHDLoad games & CD32 compilations.

I use WinUAE on my £26 Dell I3 laptop if I wanna do anything that requires a bit of horsepower as well as setting up the CF cards for my real Amigas.

Best of both worlds as I'd have to sell the kids and/or some organs/limbs to get anywhere near my WinUAE performance with Amiga hardware. I prefer playing games on real hardware it feels just a lil off thru emulation IMHO.

There are days when selling the kids to fund a new Amiga purchase seems a compelling idea though...

"Eat your bloody dinner"
"No!"
"Right, I'm getting an A3000UX and you're off to eBay"

No kidding, I was bidding on an Amiga 2000HD a few days ago, I dropped out at $415, it sold for $709. I should of bought one a year ago when you could find them for $300 or less.

I have the MiST FPGA box and the FPGA Arcade board as well as an Amiga 500. I still want a big box Amiga so I can setup a Video Toaster system to play with, it will just be a toy, I have several fast PC workstations that can do 4K video editing but I always wanted a Video Toaster when they were still relevant.

You should ask Akira if he has one for sale? On account he seems to think Amiga hardware is junk and won't hold its value. :crazy

I see prices on all vintage computers are rising a lot lately, don't know if there will be a price correction coming, does not look like it now.

I wish there were some dealers who still have stockpiles of Amiga computers, I know there is an Atari dealer here in California who just told me he has over 1000 Atari ST computers in his storage buildings, he is not ready to sell them yet, he is too busy testing and selling his 8 bit stuff to get to them.