Logic app to send logs to Azure blob storage failing

You can't increase the buffer size, so you will need to reduce the amount of data you save in one go.
This can be done either by adjusting the time interval (for example by doing it in 30 minute intervals instead of 1 hour intervals), or by splitting in a fixed line of records interval (for examply 5000 lines a time).

The post below explains this in more detail.
https://techcommunity.microsoft.com/t5/integrations-on-azure-blog/how-to-use-logic-apps-to-handle-large-amount-of-data-from-log/ba-p/2797466

You never know how much logs will be present in a specific time interval though, especially since the environment might be growing, so the only way that will (most likely) not require re-adjustment is to do it by fixed line of records.