Spain: Lawyer, bank, property developer (usually their internal compliance)
everything is done through your lawyer. if you have a good lawyer you can avoid local banks which means less headaches.
Andorra: Prepare for pain. Also have a good lawyer who can ease the pain. Everyone needs your SoF (lawyer, banks, notary, government) - full story, tax returns, payslips, police records from passport country + country of residence if different. Banks are bs, you basically need a bank to pay your property bills monthly and they'll force you for to lock up a 100k-500k deposit, and you will have no choice because you have only 3 options (Andbank, Creand, Morabanc). Worst banks with total idiots working there. But if you manage to get in - enjoy the 10% taxes and ski slopes.
Latvia, Estonia: Notary. Can use
crypto to buy sell properties. Depends on your passport, generally payslips/dividend/general crypto SoF docs are fine.
Portugal: Notary, lawyer. Can use fixers who take your crypto, provide you with SoF and manage the whole deal for 3-5% fee.
You need a good bank initially (with SEPA) where your statement looks clean and tidy. Then your payslip/
dividends/crypto docs. And in most cases you just wire directly to a local lawyer or the notary's deposit account (avoid the "you need to wire from a local bank" scam or change the lawyer). It's best if your bank matches your residence country.