GnuCash user here. Have been using it for almost two years. I never even tried to get bank sync to work, I don't think it works in Europe. But the process isn't entirely manual - it usually just involves uploading bank statements. Many banks (or credit card providers, etc) will let you download statements as QIF or OFX files, which are supported by GnuCash. Those that don't will usually at least let you download as CSV files which you can also import into GnuCash (and tell it which columns it needs to look at for transaction amounts, etc). GnuCash will then try categorise the transactions for you. The first few times you do it you'll need to manually categories everything; after that it will get better at guessing where things should go but you'll still need to review, and fill in the gaps.

I usually set aside 30-45 minutes a week to do this will all my accounts (I have multiple bank accounts, credit cards, brokerage accounts etc). If I do it weekly it rarely takes much longer than half an hour. Though I've been quite neglectful recently and probably have about a month of transactions to add which will be a bit of a pain.