SharePoint Restcalls slow with accpeted languages

I just discovered that if you try to call the SharePoint online REST services to get e.g. information about the fields-schema the call duration is much worse if you accept any other language than en-US.

https://[yousharepointsite].sharepoint.com/_api/web/getList('[listurl])/fields

By default the header

"accept-language:  de-DE,de;q=0.9,en-US;q=0.8,en;q=0.7"

is set. Duration of the call between 4-11 seconds.

But if you just remove the "accept-language" header (or clear it), the duration of the call is between 0.5-2 seconds.

Ok, translations can have an impact the duration duration of the call, but more than 4 times slower is a little bit to much and has direct impact on the user experience.

Is there a way to make the calls faster but still get translated titles etc.?

The same applies to calls like

/_api/web/GetList(@listUrl)/RenderListDataAsStream?...

and any other call I tested (also used SharePoint PnP to test this).