I don’t think anyone likes Noor so I don’t think she will be recommended.
Elena is a fantastic hero, just slow. But if she goes off, wow she can do some damage. I am doing her right now as my first 5* Red (I have more options than you but she was my first that I started on so I am carrying on)
I have never been against a Noor, so that says a lot, usually with HotM you get put against them rather quick.
Firstly… You shouldn’t really be picking based on defence yet - not until you’ve already got at least 15-20 maxed 5* heroes across all colours (so 3-4 per colour).
Anyway… They’re both slow, so you’ll typically need bench depth to wring the most out of either of them (stall heroes and healers).
On an attacking basis I’d go with Elena - she’ll help you with completion on maps/events (where you can potion her up) and she’ll provide you with excellent tile damage for titans (something the 4* key titan heroes on your red team like Boldtusk, Wilbur/Gormek and Guardian Falcon are poor at, if you have them).
She’ll be useful at this very long term, so you’ll get good value here regardless.
If you pull hard/regularly, maybe worth waiting - the portals worth targeting generally (ie: for all colours) will have great reds available…
I have had Elena maxed +7 for a long time. She is on my red mono Telly raid team, and titans team, and also shows up in some harder map stages and in some events. Point being that she is pretty good, and her tile damage is excellent
Noor is at 2-40 for me at the moment, and I will take her to 3/70 to have a look at her. I suspect that when I get there I will have proof that she is almost entirely pointless at slow mana. I have the rings but they will probably end up with Azlar or a second Marjana instead.
Elena, while slow, has proven useful over a long period. Noor seems likely to have a lot less utility, without some kind of buff.