How can I add an unsupported language to my iPhone?

I have and iPhone 13 (just switched from android) and I was wanting to add a language input option as well as an iPhone language to my iPhone. The language in question is Afrikaans and while I can see there is an option to add Afrikaans as a language to my phone, it is a secondary language and even if I move it to the top of the list, IOS still gives me a prompt saying that the phone will stay in English but apps that support Afrikaans will change to Afrikaans. Additionally there is no option to add Afrikaans as an input source when typing. This is especially irritating not because the script is different, Afrikaans also uses the latin script, but its frustrating because when I type on my English keyboard, in Afrikaans, the English spellcheck kicks in and makes it nearly impossible to type in Afrikaans.

Is there a way to load a language onto my iPhone? Both as a main language (to change the language IOS displays everything in) but most importantly to change the input language and spell check when typing. (I want to try and avoid using a 3rd party keyboard application as I really like the stock IOS keyboard, both aesthetically and functionally.

Thank you all so much in advance!