ETF 101

Hi all. So I've been researching on phinvest about information on ETFs outside the PH (I'm very familiar with FMETF). In fact most of the info aren't specific to ETFs but mostly on investing in foreign stocks/assets.

It seems there's so much info to unpack and it gets confusing quickly. Has anyone found a guide on how to get started with ETFs outside the PH (example US ETFs, etc.)

The tips I've seen so far are pretty broad:

a) Go for etoro or IBKR (interactive brokers) is this sound advice? Are there other brokerage firms that might be better? How are the applications and requirements for these?

b) Better to go for Irish domiciled instead of US domiciled ETFs, something about taxes. Also, the Irish domiciled ETFs are on IKBR?

c) I saw a post saying it only makes sense to use IBKR if you're investing a big amount (I saw a 1500 usd)?

Other questions:

Q1) Do I need a USD bank account? If not, is it still recommended to have a USD bank account?

Q2) What ETFs would you recommend for beginners?

Q3) What are the other watchouts in going for foreign ETFs? So far I saw comments on not picking two ETFs that already hold the same stocks.

Q4) Any other recommendations or questions I might have missed?