Would 董 be a possibility? (Thinking a great deal about rulers in the context of conduct and character lately, and 董卓 keeps jumping to mind;)
I don't see any reason to rule out choosing 董 as part of a name. People may be impressed by your historical interest, which can be a good conversation starter.
As for more "conventional" options, one way to see different ways of rendering a name (such as "Donald") is to look at how names of famous (or infamous) people with the name are transliterated.
E.g. Donald Knuth (a famous computer scientist) is 高德纳 Gāo Dénà;
Donald Tusk (a Polish politician) is 唐纳德·图斯克 Tángnàdé Túsīkè
To make one's name sound more "Chinese", some people will try to keep 1 surname character, and then 1-2 given name characters, to have a 2-3 syllable name like most Chinese people. So Knuth's Chinese name will sound much more "Chinese" than Tusk's, comparing the examples above.