How many HDDs in a NAS if I'm expecting to move overseas?

I used to have a 5-drive unRAID setup. A few months ago I suddenly had to move overseas, and needed to find some way to transport both my NAS and my personal desktop to a different country. Trying to figure out a solution was difficult and painful.

Transporting the drives

The usual advice is to bring your drives as carry-on on the plane.

Airlines usually have a 7kg weight limit for the carry-on. A drive weighs about 0.8 kg, when you also add in padding and bubble wrap each drive averages about 1kg. Realistically, I can only bring a maximum of 6 drives in my carry-on unless I want to risk going past the weight limit.

However I also needed to bring my personal computer, I have a 3090 in my own computer and I wouldn’t want to put it in my suitcase and risk the airline losing it. If I also bring it as a carry-on then that adds 2kg, limiting the number of drives I can carry to 4.

Transporting other NAS components

The case, motherboard, and power supply are quite heavy. I also need to move my desktop as well. It is hard to carry them in my suitcase without going past the 20kg limit, it’s even more impossible to add them to my carry-on.

For my last trip I tried to sell my computer parts before leaving, but I wasn’t able to sell everything in time and also needed to discount the prices heavily to get anyone to even consider my computer parts.

What is the best way?

I still haven’t setup my NAS setup yet, I haven’t even checked if my 5 drives are working after moving overseas. I’m now starting to plan my next NAS build and I have a few questions.

Hard drives: According to reddit I should absolutely carry these as carry-on. For 3.5" drives that limits me to 4-6 drives. If I used 2.5" drives I could potentially carry more, but these are hard to come by and are more expensive. I’m planning to limit myself to 4 drives maximum, and buy higher capacity drives (e.g. 8TB).

Other components: Selling them locally then rebuying them after moving is extremely costly. I’m considering shipping the NAS (without the drives) separately but that requires I have a destination address to receive it.

I have a few questions:

Am I necessarily limited to 4 drives? Is there a way to safely transport 5+ drives overseas?
If I’m going to ship my NAS overseas, is it worth building a small form factor NAS? This would make shipping much easier, but limits me to 4 drives since that’s the max SATA ports most ITX boards have. SFF builds are also much more expensive.