Just apply to literally any other college.
Trinity does not offer anything for maths other colleges do not, except for a historical association with the subject. THat does not actually translate into any material difference though. As a result of that though it is so incredibly oversubscribed for that subject that students with straight A*s across the board (A-levels and GCSEs) and good performance in SMC etc, are not even interviewed - and if you don't get interviewed, you can't get pooled, which means the system designed to stop students from getting edged out by competition normally when applying to an oversubscribed college does not work.
There is literally no reason to not apply to any other college. Want a large traditional architecture central college? There are plenty of other options.
Once again I will point out: it has no bearing on the academics of the course which college you go to. Lectures are centrally arranged by the departments, and you can have supervisions at any college, not just your own, dependent on where your DoS arranges them. Non-Trinity students can get supervisions at Trinity and Trinity students may have supervisions at other colleges.
Choosing to apply to Trinity for maths rather than anywhere else at Cambridge just drastically reduces the chances you'll get in for exactly zero benefit or even different in experience.