After being disappointed with the weight of the Nokia T10 for the purpose of ebook reading, I searched for a lighter tablet. Thanks to the amazing search filters at GSMArena, I was able to find Lenovo Tab M7 (Gen3). This was the lightest tablet I could find, almost weighing the same as the Kobo Sage. The model number is TB-7306F which does has Wifi and micro-SD expansion, but does not have LTE.
Slide up from the very bottom to see the full list of installed apps.
Extremely light, feels just as light as a ebook reader. The edges feel a bit sharp and metallic. But once I got a TPU case for it (from AliExpress), it felt much nicer to hold in the hand.
Multiple users: This tablet is designed to be used by multiple people in the family, each with their own Google account (both adults and kids). To add new users who can use the tablet go to Settings -> Multiple Users. However, DO NOT USE THIS FEATURE, it is garbage! I got locked out of my main admin account when I used this feature every time I used it (I tried it twice). Details here on how I had to factory reset to fix that.
USB debugging: Having USB debugging feature enabled is important in case there are problems with the tablet. To do this go to Settings -> System -> About Tablet and tap 7 times on the Build Number. This adds Developer Options in the About Tablet menu. Open it and enable USB debugging and also Wireless debugging.