@Daren ********
While not all Immigration offices did, Chiang Mai Immigration implemented the announced changes in 2020 (see link) - only need to file a TM30 on first arrival. I've not only confirmed this directly in person with them, I've filed 90 day reports in person and new extensions of stay using TM30s filed prior to having left the country multiple times.
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48/tm30-reporting-rule-on-foreigners-eased