I have temporarily switched from my 64-bit, x86 laptop with a dual-core, 1.5GHz Celeron to the ASUS Tinker Board single board computer /w a 32-bit, quad 1.5GHz Rockchip CPU, the exactly same one as used in some models of the Chromebook.
I have, however, experienced much worse performance when playing on large maps - something that the Celeron had no problems dealing with.
So, I'd like to ask, if it may be either the ARM architecture or the 32-bit CPU slowing the game down.
I also have to note that now I have 2GB of RAM, as opposed to 8GB in the laptop, but I've never seen OTTD saturating the 2GB on either machine.
---OT: I really can't express enough how impressed I am with the compatibility of this game over all the systems and platforms it can run on. I've never seen a game that would allow for crossplay multiplayer between Android, Windows, Linux Mint, MacOS and even the Armbian, all at the same time with no issues