It's great that you're spreading the word but this must be done strategically, not just dumping a bunch of posts at once on random communities especially since they are all from your own blog.

Keep it to a slow trickle of info and not only will people be less annoyed but they also will have repeated, organic interactions with Meshtastic over a longer period instead of it being forced upon them all at once with spam.

The way you're doing this they will disregard your posts and think the MT community is annoying and not worth engaging with.

Check out !meshtastic@mander.xyz

~~I've been looking to play with Meshtastic, but I've had a difficult time finding hardware that's compatible with its firmware~~ Nevermind, that's Reticulum and the RNode.

As others have said, maybe try posting some of that content natively to Lemmy for discussion. It's sadly not uncommon for people to create accounts on here just to drive up engagement of their other blogs (without participating in the Lemmy discussions beyond spamming links). Those tend to get treated harshly by default.