A smaller split sounds like it might be a good option for you— a Sweep, Corne or something similar. I’m biased towards Cornes— mine is a mini 5x3. I’ve found it to be really good for travel. Packs light, and works well on train journeys (table or back of the seat fold-down).

Also, I support that notion of experimenting with your own build. That’s exactly what got me where I am. Bought a prebuilt Lily58, then a full sized Corne, then wanted to make one myself and bought an Aurora kit. No soldering experience, and I found soldering the backlighting LEDs most difficult (I’ll be removing them sometime soon) but my board works and I’m extremely happy with it. :)

I’ve got a 5x3 Aurora Corne, plate case, large stand-offs so I can fit 1500mAh batteries under the board. Makes it a bit “high” profile, so to speak, but I’m okay with it.

Are you putting backlighting in your build? If so, that’ll be the biggest power drain. I built my board with backlighting, although I’ve never use it. Even so I get about a week out of the right side and a few days out of the left. Planning to pull the LEDs out at some point in favour of better battery life.

Depending on the case you pick you should be able to find one with enough space in the base for decent sized batteries. I was looking at some Scottokeebs cases at one point (https://www.etsy.com/uk/listing/1452267605/corne-keyboard-3x6-3d-printed-case-wired); one reason I didn’t go for in in the end was because the cutouts weren’t in the right places for the Aurora PCBs controls— mainly the power switch. Give some thought to what you actually need to access with respect to any case you get.

Apologies if any of this is obvious!

:) At the time, I didn’t even own a soldering iron, and I wouldn’t have known what to do with it if I did!

Repairing that battery myself later down the line was the first bit of soldering I ever did, which allowed me to then go on and build my first board.

If I’m reading you right, glad to hear you’re all sorted.

Not sure I 100% understand what you’re looking for, but for a while I used a pair of 16340 batteries with shields /charging modules. One of my installed lipo batteries had failed and at the time I didn’t know what I was doing with soldering. I attached the 16340 shields to the underside of my Corne and used them to tent the halves with ultra short USB-C cables to power my nanos. Sounds a bit hacky, and it wasn’t a pretty or permanent solution, but it actually didn’t look too shabby, and it was functional.