ETF's currency and certificates

[congnh2412]

Hi, I am new to ETFs and will appreciate if someone answers my queries below.

I bought shares in a couple of ETFs recently thru Degiro using an euro account.

One ETF which is in euros (Xtrackers iBoxx Sovereigns Eurozone Yield Plus UCITS ETF 1C LU0524480265/XY4P) I got thru XETRA and the other ETF (iShares J.P. Morgan USD Emerging Markets Bond UCITS ETF (Acc) IE00BYXYYK40/JPEA) on London Stock Exchange which is in USD.

I have a couple of questions regarding selling my ETFs in the future:

• do I have to use the same broker? if not, how do I get a proof/certificate that I own these shares?
• where are my shares physically located?
• since my portfolio is shown in euros, is my second ETF physically held in USDs? (iShares J.P. Morgan USD Emerging Markets Bond UCITS ETF (Acc) IE00BYXYYK40/JPEA), in other words: when I sell all the shares of this ETF, will I be buying euros at the future exchange rate for the amount of USDs in my position?