Should I mark my general ledger account/expense category as "Other COGS" or "Other Business Costs"?

Good question, this doesn't have tax implications, just reporting implications for your business.

The "Other COGS" accounts will show up under the Cost of Sales section on your P&L, while "Other Business Costs" will show up in the "Other Business Expenses" section of the P&L. If you're confused by the "Cost of Sales" section on the P&L, run a P&L and hover over the info icon to learn more about the sections of the P&L.

The principle is that if an expense category is directly related to your sales process, you want to mark it as "Other COGS". Expenses that are not directly related to your sales process should be marked as "Other Business Costs".