Before you go an ED visa route, I suggest to consider a _multiple_ _entry_ tourist visa. That would give you via leaving the country and reentering and extensions of stay close to 9month of stay. It should not be a problem to get a second one afterwards, and makes no hassle in simple letting it expire. An ED visa on the other hand needs to be canceled, which means an extra visit at immigrations.
That said, regarding ED visa and my assumption from your photos, you might be interested in Self Defense (as a sport, not out of other reasons) or close combat. In Chiang Mai are several "martial arts" gyms that offer self defense, close combat or martial arts with one year ED visa. I can recommend
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EDIT: P.S. perhaps your employer gives you an option for a one year sabbatical - but I guess you considered that already, reading your answers to some comments :P