In version 22.6.20 the Profit and Loss Report, Summary view and Chart of Account categories do translate, although translations have been setup for the categories, e.g. Expenses should be Uitgawes, Income should be Inkomste.
This is as designed.
Income and expense groups can be deleted. So they are not hard-coded in the program like the top-level groups on balance sheet.
The same goes for most income & expense accounts.
To get these groups and accounts in your language, you need to be using Manager in that language during business creation.
You can also edit the group names after business creation. Like self-created account names, they will not change if you change language settings.