I've tested a lot Zeus on various devices. If you read my guides I included some of these tip in them. But I doubt you read them.

• memory: only in the initial phase of sync is taking up some memory, but not too much
• battery: pro tip - if you use it a lot, making payments, your channels.db and wallet db will increase dramatically. Use weekly the option of "compact database". That will reduce a lot the battery use.
  I've tested Zeus 3 whole days continuously using it in persistent mode and with compacted database and the battery was used only 50%
• data usage: most of the data usage is done by neutrino sync. If you travel a lot, I suggest to sync it more often even that you do not use it. The data used is the same and is limited to few MB.

What you have to be aware is that when travelling you will be subject to various connections and neutrino sync is very sensible to this. I wrote several guides about this aspect, please pay attention to those guides about sync issues.

• https://darth-coin.github.io/wallets/getting-started-zeus-wallet-en.html
• https://darth-coin.github.io/wallets/zeus-node-advanced-usage-en.html
• https://docs.zeusln.app/for-users/embedded-node/faq#what-should-i-do