It's simple, there's this "Star" feature on Thunderbird, so if I'm not ready to handle the mail now, I'll just click the star to mark it as important, and undo the star after I've done handling it.
Or, just like what @atrus said, don't receive emails if you have other higher-priorities.
Also it works with private repos too if you provide a personal access token (fine-grained) in the Obtainium app settings. Just make sure to "release" (on the Releases tab) the .apk file on the GitHub repo and tag it latest.
I use 'just' (command runner) and the 'gh' CLI to automate this:
In the search box, input "ISS" and filter by perigee (min: 380; max: 500). You should see the name of one of the modules of the ISS, such as "ISS (Zarya)" [0] or "ISS (Nauka)" [1]. If you can't find it on the visualisation at first, you can get its current location at https://isstracker.pl/en .