Start from the questions you will ask
A chart of accounts is really a list of the questions the owner, the accountant and the FTA will ask. The owner wants to know margin by product line and what the office costs. The accountant needs clean balances for receivables, payables, VAT and fixed assets. Corporate tax needs certain costs visible on their own, such as entertainment and related-party charges, because they may be treated differently in the computation.
If a question matters, it needs an account or a tag. If it does not, it should not get its own account. Most small UAE companies need between 60 and 120 accounts, not 400.