Need help choosing an Network provider

I just bought the Apple iPhone SE and I'm pleased with my purchase.

BUT I don't know what network provider I should choose.

I use to have the Apple iPhone 5s and I loved the phone but it's smashed to pieces now. My network provider was EE and I use to top up £5 now and then and buy the £5 everything pack where I got Data, calls and texts for £5 and it was perfect for me.

But now I have a new mobile phone and I want a new mobile number and I want a new network provider.

What other network provider provides something similar to EE?
I don't want a Sim thingy by the way.

How to put 2 videos side by side on an iPhone?

I have this video I want to make where there's one video in the left and one on the right playing on the same time… On an IPHONE. I know it's seems stupid but I'm just curious if there's just that ONE app buried with ones that don't that does this without having to pay anything.

IPhone Backup Issue?

I've been backing up my iPhone data on my mom's computer for years now, and its encrypted every time. I can't recall the password I set back in 2013 because, well, that was a long time ago. However, every time I got a new phone or had to wipe my current one, I was never asked for a password to restore my phone from a previous, encrypted backup. I just downloaded iTunes on my new laptop and backed up my phone to this laptop before wiping it. However, now to restore I'm being asked for a password, which I don't have. If I go back to my mom's computer, will I be asked for a password as well or should I be able to restore it like in the past? I appreciate any help!