ma Mosijo for Hungary is objectively terrible as far as transliterations go, though I quote like that it's one of the very few if not only that changed very early on (2005 iirc -- it was Masija, which was too similar to Asija).
The 'gy' /ɟ~ɟ͡ʝ/ in magyar* becoming an /s/ is just weird, though can be reasoned (/ɟ~ɟ͡ʝ/ > /dʲ/ > /di/ > /ti/ >** /si/ -- the semivowel then added back), it's still one syllable too long. 'a' is an /ɒ/ in Hungarian, that becoming an 'o' is arguably acceptable (although I'd argue against it, but given the circumstances, I won't complain).
Better solution? "Mata" for Hungarian could work I guess, all I know is that U'd greatly orefer having a plosive in it than a fricative.
*: the country's name is Magyarország, where magyar=Hungarian, ország=country **: by toki pona syllable rules
mi ken toki kepeken toki Mosijo en toki Inli en toki pona.