@lineal
Hmm, at least on DietPi installing MariaDB by default sets `innodb_file_format=Barracuda`, `innodb_large_prefix=on` and UTF8 table collation. From the issue you linked I could not 100% reliable get that this is sufficient, however perhaps worth to try? Also there is a post install solution provided by altering the table manually, though a bid hacky.
EDIT: If you want to try it out, tell me first. DietPi's Nextcloud install allows automated backup migration, if you place the old install dir and database dump into certain folder structure.
Installing MariaDB 10.2/3 on Debian Stretch is definitely the harder work. Adding the Buster repo leads to a rats tail of installing many possibly incompatible dependencies, otherwise a custom build would be required.
I run my DietPi Buster on my RPi2 successfully, using
https://github.com/Fourdee/DietPi/issues/1285 on top of Raspbian Lite

. However I can absolutely not recommend it. Debian Buster works flawlessly but Raspbian Buster regularly has critical APT repo issues that are veeery annoying and you have to take care to not destroy your system or have a bunch of packages removed due to dependency conflicts. See:
https://github.com/Fourdee/DietPi/issue ... -429478836
At least we could just fix a MariaDB 10.3 issue with latest DietPi version due to deprecated settings. Switch from 10.1 to 10.3 was just some days ago.