You automate all the recurring things (this is built into Gnucash), enter the non-recurring things (takes a minute or two a day if that day even had any transactions) and reconcile against the bank's statement/app/website monthly to make sure its representation stays accurate.
Once you've entered a transaction once, its autocomplete handles those going forwards so entering a new transaction is as quick as typing the first couple of letters of the shop name, pressing tab a few times, then entering the amount.
Once you've entered a transaction once, its autocomplete handles those going forwards so entering a new transaction is as quick as typing the first couple of letters of the shop name, pressing tab a few times, then entering the amount.