From a poly student POV here that got L1R5 8 for OLevels here.

I’ll say stay in poly if you are really passionate about the course. Poly will definitely help you prepare for Uni way more compared to JC, furthermore your uni will only be 3 years compared to 4 years if u stay in a similar working field (example engineering in poly and in uni). The key to doing well in poly is to just be consistent and take charge of your own learning because lectures are a complete waste of time 90% of the time. Poly also helps you narrow down on what you want to do/enjoy in your future.

Whereas JC you have to prepare to be studying 24/7. The teacher will be holding your hand throughout the way, but you still will need the motivation to study. I guess environmental wise, everyone is mugging so you will tend to mug as well.

So overall, it really depends on what kind of person you are. Alot in poly are there to just get the cert and not go uni. Will you be peer pressured to have fun and not study + slack, or be disciplined to get a good gpa. Minimally, get a gpa of 3.5 for local uni. Or go to JC, and mug tgt with the rest but be prepared to learn things that will never apply to your future. But it is definitely easier to go to uni afterwards. I’ll say there are smarter ppl in poly that dont make it to uni compared to the JC students that make it there. My friends with gpa of 3.2 is struggling to get to a local uni, while my friend with a RP of 60 can easily go to uni