There has been research on the intersection of IoT and PQ signatures specifically at least, e.g. see "Short hash-based signatures for wireless sensor networks" [0] [1]. Unlike SPHINCS+ which is mentioned in the article, if you're happy to keep some state around to remember the last used signature (i.e. you're not concerned about accidental re-use) then the scheme can potentially be _much_ simpler.

[0] https://web.archive.org/web/20110401080052/https://www.cdc.i...

[1] https://news.ycombinator.com/item?id=33925383 I wrote about this "Dahmen-Krauß Hash-Chain Signature Scheme" (DKSS) algorithm previously in a comment a couple of years ago