Saying sleeves make shuffling worse is backwards for me, since bare cards get sticky and clump after enough plays. But you're right that most games don't need them, just don't let Wingspan get too worn or a marked card will give away the deck.

Ran into the same thing last year when I moved my old Crucial MX500 into a spare bay just to have a second Windows install. Boot times were within a couple seconds of the new drive and for web browsing and email you would never know the difference. The gap only shows up when you move big files or load huge games, and that is where the NVMe earns its keep. For most folks doing basic stuff, the money is better spent on more RAM or a clean install of Windows. Pull up Task Manager during your normal work day and watch the disk usage, if it sits near zero most of the time you already have your answer.

Opendoor is fine if your house is basically perfect. If it needs any sort of work, their "repair costs" will shock you.