Worth looking at:
Turris Omnia (older) and Turris NG (latest).
https://www.turris.com/en/
The software and possibilities, what power consumption comes with them.
They have storage (Omnia - mSATA, M.2 the NG), 2G RAM, USB, the ability to add a Wi-Fi card of user's choice, and also a modem (2x mPCIe).
BTRFS (with schnapps) - one can undo harm done by wrong configuration with ease (a kind of recovery mechanism).
So it's nice to play around with.
OpenWrt compatible also.
Both equipped with a SFP+ so the routing capabilities are high (yet the Omnia can't saturate full link speed with use of the WireGuard).
Overkill for the transportable HW, that's for sure. They are meant for SOHO.
And of course, the OpenWrt One (USB-C PD or PoE, M.2, dual boot for recovery).
https://openwrt.org/toh/openwrt/one
All also using an RTC (button cell).
