You're not alone on this: Ibanaham just asked EA for the same event dictionary in "Request for Complete FC 27 Clubs API Event ID and JSON Definitions", with 96 distinct event IDs in one match file. Pooling your decoded IDs might get you both further.
On the FC 27 league matches I've looked at, each aggregate is a comma-separated list of id:count pairs, for example 174:5,175:3,215:8. If you end up with a reliable list, I'd be glad to add the labels to proclubs-sdk, the open-source Node.js client I maintain for these endpoints, so other tools can use them too.
