Please be aware that that TinyLoRa doesn’t receive any of the network commands that are sent by TTS so there are some configuration details that will reduce the gateway transmissions - you need to set all eight frequencies so that they repeatedly sent as a setup and ideally tune your data rate for the distance from the server - the stack may still try to send ADR commands but at least your DR will be good for the radio environment.
I haven’t revisited the Pico option of late, there wasn’t a feasible way to reduce sleep power consumption when on battery without too many shenanigans.
However my toolkit of modules has increased so it should be feasible to take this for a spin - if only to benchmark some edge ML libraries on the Pico which, with solar power (a rare event in Bolton), may make the Pico viable with some external timer chip.