Is it easy to use and import transactions from credit cards?

I wouldn't say it's easy to get set up. If you don't mind exporting transactions from your bank, and importing into Gnucash, that part isn't too difficult. I like Gnucash a lot, although I've fallen behind with keeping up with it in recent years. I was never able to figure out the online banking side of things, but that's ok. I also never used it for budgeting.

Yes, atleast for me. then I left with a feeling of double checking the stuffs often which ended with opting in for Ledger/BeanCount as the final solution. Checkout the PlainTextAccounting sub...

Tried it but I also hate the manual import and categorization. Had much better luck with Empower (formerly Personal Capital), though they're not OSS

Import of transations is via a CSV - I do it once a month and then shred the receipts that match. It's a bit clunky compared to quicken on windows (last I used it was 2018), but it can do the job, and of course it's double-entry and free.