DIN standards are local derivatives of ISO standards.

There are few widely used "Technical lettering"[0] standards: «ISO 3098»(EU/International), «ASME Y14.5»(US) and «GOST 2.304»(ex-USSR).

There are few FLOSS fonts which cover «ISO 3098»[1,2,3], «ASME Y14.5»[3,4,5] and «GOST 2.304»[6,7,8] technical lettering standards.

[0] https://en.wikipedia.org/wiki/Technical_lettering

[1] https://github.com/hikikomori82/osifont

[2] http://peter-wiegel.de/TGL.html

[3] http://peter-wiegel.de/TGL_0-16.html

[4] https://www.fontspace.com/micronus

[5] https://cstools.asme.org/csconnect/CommitteePages.cfm?Commit...

[6] https://bitbucket.org/fat_angel/opengostfont/

[7] https://github.com/Metrolog/Font.GOST2.304-81

[8] https://github.com/MishkinIN/Font_GOST_2.304

Seems like ISO 3098 is significantly newer than DIN 6776, so it's the ISO standard that's derivative of the DIN one.

Well, you are partially right, because most of "DIN" standards already replaced by "ISO".

But there are still many "DIN" standards that now replaced by "DIN EN ISO", e.g. German (local) version of «ISO 3098» (which replace «DIN 6776») is «DIN EN ISO 3098».[0]

[0] en.wikipedia.org/wiki/List_of_DIN_standards#DIN_6000_to_DIN_6999