Dedicated Player Recommendations / Long Battery Life?

Can anyone recommend a simple mp3 player to listen to audiobooks? Is the MECHEN X55 (claimed 2000mAh) Android 10 one any good?

My background: I am currently using Rockbox on a ClipZip player, unfortunately the thing is failing and most newer models don’t run Rockbox.

AGPTEK players have 60h battery life, but don’t run Rockbox, and their firmware misses basic features of Rockbox, such as automatic bookmarks for audiobooks: I can’t easily go back and forth between different books. Rockbox automatically stores one bookmark per folder, so it is very easy to switch as long as each book series is in a separate folder.

Now I am thinking about getting an Android player + AntennaPod, but they tend to have short battery life, often < 10h.

I sideload my books and don’t care much about any other streaming apps. The outdated Android players are unsafe to connect to the network anyway.

Is AntennaPod + Android the way to go, or should I look into a DAP that runs Rockbox, like the HIFI Walker H2? Unfortunately these also have very bad battery lifetime around 10h.

HiBy R1 also looks good (non-Android, Rockbox), but only 15h play time claimed.

I use the Smart Audiobook Player app on my Android phone.