My credit cards I’ve had in Germany/Austria were all basically glorified debit-cards which had their own bank account attached to them. Technically I had a credit limit of a couple thousand, but I never went into the negative.
The only difference (for me at least) was that I could use them to rent a car, which is nice.
Personally I always always buy phones with two sim slots. It’s super practical if you travel semi-often.
Idk about apple, but basically all of the mid-range androids have this feature. I guess this is about the US though, so it’s probably Apple.