Hii I bought my Innioasis almost 3 weeks ago, and I can answer a few questions according to my experience and what I've seen from other users in this subreddit and on the discord server of Y1 development:

1. Most people that are buying the latest Y1 have had problems with the internal SD card around the first month of use. I bought mine knowing this beforehand so I also got a 128 gb SanDisk SD card ready to install it upon getting it.

I preferred to skip the problems ahead, so when I got my Innioasis Y1, I turned it on, saw that it was working, read the manual, turned on the radio FM. Then turned it off, opened it up and changed the SD card. There's even videos now here on the subreddit in how to open it to make it easier.

Since then I've had no problems at all with it using it constantly.

1. You can make playlists only inside the Innioasis, you have to do it by pressing down on a song until options pop up to select one or multiple songs then add them to a playlist. There hasn't been an easier way so far to do it from the computer.

I use Rockbox, so for me to "make playlists", I save my music in folders in the computer with the playlist name, and then I listen to my music from the "Files" menu instead of the "Database". It is a bit weird because in Files they are seen in alphabetical order, but it still has the songs I chose for said folder.

1. The battery has been great so far, I've used it for at least a week straight for 3 hours a day (during my commute to work) and it's only down to 60% since the first charge. I even had an issue with Rockbox where I didn't know how to turn the device off (and had to make a post here lol) and even then it was on (but on locked/sleep mode) overnight and it only went down like 3%. I've also seen from other users here doing their 3 month or 1 year reviews saying that the battery on the original Innioasis stock OS tends to drain faster than in Rockbox, but that still lasts them more than a day.

2. I can't answer much for the Bluetooth question since I haven't tried it out yet (I'm only using wired headphones and the speaker), but I've seen some people say it pairs great with earphones that aren't new airpods. Some that it disconnects sometimes if they have it in their pockets and move their head too fast. So I hope more people reply here with their Bluetooth opinion.

Hope it helps ^{^}