does supabase do rate throttling for the free tier, cuz occasionally all my supabase requests just don't go through for like 30 seconds, then everythings back to normal

You're limited only by the power of the instance/VPS that it's running on. On free tier, that's a T4G.Micro (https://aws.amazon.com/ec2/instance-types/t4/) which has 2 CPU cores and 1GB RAM. 1GB is close to the lowest you can realistically run the Supabase stack on. In terms of API request count, without knowing more specifics about your use case and the number of users you have, it's difficult to say exactly how many API calls would be considered 'too high'.

my request sizes are fairly large around 100kb