Do you have much of your own music (i.e., downloads)? I went through this same process about a year ago (to upgrade a from an iPod Classic with a dying battery), and storage capacity was one of the biggest differences across DAP models. I needed as much as I could get, and that narrowed my choices considerably.
If you’re looking for WiFi for streaming, you probably do pretty much need a touch screen. How are you going to search for music (e.g., typing in artist, song or album names), or browse a collection? I may be wrong, but I don’t think DAPs have adopted voice recognition yet—at least I haven’t heard of any. After storage, user interfaces were the next biggest deciding factor. I was surprised by how many players I found with glowing reviews for sound quality that also had slow, poorly design or buggy user interfaces. Try to figure out if the UI is any good from reviews, videos or hands-on time if possible.
Since you specifically mentioned Spotify, make sure that’s compatible with any DAPs you look at. Spoiler: I ended up with an Astell&Kern AK380, and it natively supports Tidal, but I don’t think it will work with Spotify? In any case, some newer DAPs support downloading apps to work with a variety of music services, whereas most older ones seem to be closed systems where you get what you get. I may be wrong about AK380 and Spotify since I don’t use Spotify. FWIW, Tidal has been excellent for HiFi streaming.
Apart from that, I started my search by looking up “Best DAPs” on Google and then digging into the various models to figure out their limitations. FWIW, Astell&Kern seemed to dominate most of the lists and searches I found. Based on my AK380, I can see why: very good UI, extremely good sound quality, great storage capacity and—in the case of the 380 at least—tons of secondary capabilities, like the ability to act as a music streamer for a HiFi setup. You’ll pay through the nose for A&K, though, so shop around and see if any competitors check enough boxes to get you more bang for your buck.
Hope this is enough general strategy to help you with your search. Once you start narrowing your choices to a few interesting models, ask some specific questions about them and I’m sure you’ll find people with experience who can help you to make a final decision, Good luck!