What is the opinion of Reddit about the
Foldable Bluetooth Keyboard, Gimibox Pocket Size Portable Mini BT Wireless Keyboard with Touchpad for Android, Windows, PC, Tablet, with Rechargeable Li-ion Battery-Dark Gray?

I’m using an older Anker bluetooth kb that I don’t see listed on Amazon anymore, but it works great.

Eyeballing this foldable one with trackpad, though: https://www.amazon.com/Foldable-Bluetooth-Gimibox-Rechargeable-Battery-Dark/dp/B08BCBFQS7/ref=sr_1_20?crid=3KYYUJ9VRYNL6&keywords=anker+bluetooth+keyboard&qid=1648677928

Amazon, I’ve got 4 or 5 different ones by now.

Here is one of my favorites.

Yeah I hear ya and it’s great you enjoiy doing it anyways.. I do not enjoy doing it lol but I will if I can because I hate throwing working things away or re-buying things etc. The only battery that actually REALLY pisses me off is my phone battery. I don’t want to buy a new phone, but my battery , but replacing the battery looks like a nightmare to me, I need tools I don’t have and it requires an almost 100% teardown. Obviously phones can’t use AA batteries and thank god for that lol but every phone I’ve had before this one had a stupid simple battery replacement where you just pop the back off and swap the battery.

Anyways enough of my ranting, I tried to look for something that fit your requirements, but it seems damn near impossible. I found bluetooth but AA or AAA batteries, or rechargeable batteries but a 2.4ghz USB adapter. I did find a couple of options though, but they have their own quirks as well.

This one is close, but it’s foldable. No idea what these are like to use:
https://www.amazon.com/Foldable-Bluetooth-Gimibox-Rechargeable-Battery-Dark/dp/B08BCBFQS7/

I also found this one that looks like the bottom half of a laptop:
https://www.amazon.com/Wendry-Bluetooth-Touchpad-Keyboard-Ultra-Slim/dp/B07QW2LXVG/

I also found a couple of mini ones that are Bluetooth and rechargeable
https://www.amazon.com/Rii-Bluetooth-Keyboard-Smartphones-Mac-Black/dp/B07T13GLY3/

https://www.amazon.com/Fosmon-Portable-Lightweight-Bluetooth-Controller/dp/B00BX0YKX4/

https://www.amazon.com/Rii-Wireless-Touchpad%EF%BC%86QWERTY-Bluetooth-Connection/dp/B07TS7TQ8J/

The only ones I could find in any price range even that were Bluetooth and looked like a K400 are these ones that take AAA or AA batteries
https://www.amazon.com/Multi-Device-Bluetooth-Keyboard-Touchpad-Multi-Touch/dp/B09C1BVCLB/

https://www.amazon.com/Arteck-Universal-Bluetooth-Multi-Device-TV-Connected/dp/B08SK8D38P/

Who knows what the battery life is on those things though, but probably not the 18 months of the K400.

Anyways, I hope that helps in some way, good luck