According to their April 1st committee finance report, they've been making a lot of payments to eztexting.com for their "mass texts to supporters expense" and eztexting claims to have a "SafeSTOP" compliance so you could try reporting SAN to them. Source: about 3 years ago

Third-party SMS and MMS messaging apps already exist on Android, such as QKSMS,[1] Simple SMS Messenger,[2] and a large number of proprietary apps. There isn't a shred of evidence that these non-default SMS/MMS apps increase spam to any measurable extent compared to SMS/MMS apps that are preinstalled on phones. [1] QKSMS: https://github.com/moezbhatti/qksms. - Source: Hacker News / 6 months ago

Try QKSMS it is more visually pleasing. Source: about 1 year ago

The current version has not been updated since 2021 (2+ years ago). Source: about 1 year ago

I installed this custom kernel ROM¹, disabled google services through Settings > K Settings² > Disable Google Services, rebooted phone³ and then uninstalled every google package via UAD. I use QKSMS [Github | F-Droid] now and everything works fine. Source: over 1 year ago

I'm thinking of switching to something like QKSMS as my default, because it looks less annoying than the stock one. However, if there are any apps that allow encrypted messages between registered users (like the old Signal) while also supporting SMS to non-registered users, then I think that would be the ideal option. Source: over 1 year ago