No, it's very comfortable to hold actually. My Switch Lite feels cramped by comparison.

I am almost always resting my arms when I'm playing on the steam deck. It's not mandatory but it's just more comfortable in general.

Its harder on the back-neck than something like a GBA, but compared to the switch, it isn't night-and-day. With basically anything larger than a phone, you're probably going to be resting it on your knees or a table anyway.

Definitely much heavier than something like a Switch. It's not something I would use while standing on a train like I would with the Switch. I only ever play with it seated and have it laying on top of my bag on my lap.

I would love it if they had one similar to the Switch Lite's size but that seems pretty impossible with the current chipset.

I plop on my couch and put a throw pillow on my lap and put the Steam Deck on the pillow. So I'm not really holding it. My arms do still get tired, but only after playing for hours at which point I should probably take a break anyway.

I only notice the weight when i drop it on my face. Otherwise it just feels like a phone.

They don't get tired but I have inadvertently given myself Cubital Tunnel Syndrome. Numb Pinky, and Ring Finger from leaning too much on my elbows playing. Think Funny Bone except it happens without an injury, and it doesn't go away immediately.

As long as I can rest my elbows somewhere it's fine for hours. And because it's bigger I get way less cramps in my fingers than for example the switch. That one I couldn't use for longer than an hour.

I held it and tbh its not as big as people think it is, they imagine a huge massive handheld (and so did I tbh) but in reality its not even the same size as a full sized controller

I played for like 8 hours straight yesterday, yes my arms and fingers hurt a bit but are fine today.

No