OP, you have asked a general question related to a specific context. In terms of the specific, as others say, it is sensible to engage with the school about your DD; you may be planning this anyway.
In terms of the general, PPs indicate a wide variation in approaches by schools. You can dig into the detail for your DD's school and other state schools via the Gov link I give at the end of the post. This shows average GSCEs taken and breaks down by prior attainment (ie SAT score bands).
My DC went to a non-selective comp with a very mixed socio-economic catchment. The approach is that students sit 11 GCSEs (inc 3 science, RS, plus 4 options) unless there are compelling reasons otherwise. In practice a substantial minority take 11 in one sitting, the majority take 8-10 (dropping RS and/or taking only 3 electives and/or taking double science). The remainder take 7 or fewer GCSEs and/or combine with other qualifications.
The school has good progress 8 scores for students at all levels of academic ability. The trimming of GCSEs taken is done logically and sensitively at different stages.
I am interested to hear that a large number of schools, particularly private and state GS, cap the total number to ensure a smaller number of better grades for their own stats and for entry to competitive unis. I understand the logic but it does risk forcing subject specialisation even further down the age range.
My DC ended up with a mixture of GCSE grades, and probably partly because of the number taken, but did develop the confidence and skills to manage a large and varied workload and closed off fewer future pathways (this proved useful for both); they and I also knew that GCSEs could be trimmed if necessary and that would not be perceived as abnormal or somehow 'bad'.
Different posters will have different perspectives and there is no single correct answer. I simply wanted to suggest that it is too simplistic to say 'fewer is always better' and that there can be benefits to stretching students so long as sensible systems and expectations are in place.
www.find-school-performance-data.service.gov.uk/