ErgoMechKeyboards

You're kinda all over the board on which keyboards you're looking at, 36 to 80 key keyboards, some with keywells, some without, some by big companies, some open source made by solo vendors. If you're looking for just a list of keyboards to browse through, you can checkout the wiki here and focus on vendors in your region: https://gitlab.com/ergomechkeyboards/wiki/-/wikis/useful-resources. If you're looking for recommendations, you'll probably need to give us more than just something to travel with.

I would say that keywells don't make for very travel friendly boards. If you want a big company build (OEM), I think the ZSA lineup (ergodox, moonlander, voyager) are going to be the best travel boards. If you're looking at open source boards (corne, skeletyl, etc - DIY boards, they're called, but you can find solo vendors to do the complete build for you), then pretty much any flat board you find will be better to travel with than a skeletyl or glove80, and from there you can choose as many or as few keys as you want. For either DIY or OEM boards, I would just browse the list of vendors in the wiki link I posted above.

Glove80 will have a case made for it very soon. Might want to take that into account.
The case compared to the Advantage360

Do you want a prebuilt board or are you happy with some DIY action?

you could build a smaller dactyl so its like the Advantage 360 Pro but it not the nicest to take with you

I mean this is what https://reddit.com/r/ergomobilecomputers is for . Try searching there for 'sonshi' setups so you can just put a small ergo keyboard on top of your MacBook.

one example is the corne: https://Reddit.com/r/ErgoMobileComputers/comments/u3xcfb/ergomechkeyonlaptop_corne_foldout_travel_case/

It's been a minute since I first create this post, but I want to provide an update. I have purchased a ZSA Voyager, and I am eagerly awaiting its arrival.

What finally made me commit was Ben Vallack's live stream about the Voyager. Thanks Ben!

My first interactions with ZSA staff have been amazing. I found this yesterday on their blog, https://blog.zsa.io/voyager-shifted-layout/ and I think it could really be a game changer for me personally.

I'll create a new post when it arrives and I've had a chance to take it for a drive.

I have the Lily58 with low profile switches. I can travel with that very easily. Takes up about the same amount of space as my kindle with a case and keeps me typing happily.

I built mine for around $300USD.

if you can stomach the low key count I'd highly recommend something like the Sweep. if built wireless it becomes an even better travel board IMO but it's not a necessity. Also sometimes uni-bodies can make good travel boards as they work pretty nicely on your lap or other awkward situations a little better than a split. Personally I have an Osprette which I love.

The others you've listed are all good options too. Good luck.

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 just took a Sol 3 to New York for a week. Traveled in its case in my carryon.