Re: A76 L1 cache size?
The reason is physics. The further you get away from the actual computation cores, the bigger the latencies become. Therefore, you can assume that the small caches "run really fast".
What you observed is basically the dilemma of shrinking dies vs. increasing clock frequencies. ;-)
As there are no fixed/standardized sizes/clock freqs. for caches, your question is hard to answer. Nonetheless, here's a links with a few examples (AMD Ryzen and Intel Core i7):
https://www.techpowerup.com/231268/amds-ryzen-cache-analyzed-improvements-improveable-ccx-compromises?cp=1
[AMD's Ryzen Cache Analyzed - from 2017]