You saying 90% of your gaming is on PC makes me think you are not going to like the quality of the 3DS screen. It's absolutely awful and was already outdated when it launched back in 2011.
You wanting to use the system to relax on the couch after putting the kids to bed also tells me it won't see much use in all likelihood so you will never exhaust the great library the system has.
At this point you might as well just go for a Switch even though it's far more expensive: the current top games on there will last you a lifetime, your eyes won't bleed because of the great quality screen, and who knows, you might love it and pay more attention to future releases.
Or just play on your mobile phone, there's a lot of paid quality games without all the nonsense to be found on there nowadays.
You wanting to use the system to relax on the couch after putting the kids to bed also tells me it won't see much use in all likelihood so you will never exhaust the great library the system has.
At this point you might as well just go for a Switch even though it's far more expensive: the current top games on there will last you a lifetime, your eyes won't bleed because of the great quality screen, and who knows, you might love it and pay more attention to future releases.
Or just play on your mobile phone, there's a lot of paid quality games without all the nonsense to be found on there nowadays.