Here is a recommendation I gave for the Anne Pro. It hits your check boxes and it's a nice board in my experience, although some minor configuration is required and a little dielectric grease on the stabilizers is warranted.
I'll shorten it up for your specific question:
This doesn't hit all of your checkboxes, but I like it quite a bit so I'll throw in a recommendation for an Anne Pro mechanical keyboard. I picked one up a few weeks ago because the robber dome boards at work were hurting my fingers. It's a pretty great board, but I'll go through your concerns so you have a decent rundown. For background, I've also got a K70 at home (cherry browns) and I went with cherry reds on my Anne. (EDIT: This board actually comes with gateron switches, not original cherry switches.)
- Low price (<=100 EUR) since this will my secondary keyboard
Usually runs about $80 USD
- Blue (or green) switches (Cherry)
Gateron switches, offered in blue, brown, and red.
There are three preset layouts and one that you can customize entirely, including the Fn layer.
The board does support macro functions through the app, and I've seen plenty of people talk about using media macros. The function is currently broken in firmware 1.4 (current version), but should be fixed for 1.5 before the year is out.
Stuff you should know:
They've got a subreddit with guides for everything to do with this keyboard if you decide to get it. Firmware update and app installation (needed for the custom preset, I haven't done it yet that's happening this week) are a bit of a pain from the looks of things, but not too bad. There is no physical power switch. The company says you can just disable bluetooth and RGB and that will put the board into a kind of sleep mode, but you'll notice on that sub that a lot of people install physical switches to kill power and avoid accidental key presses while carrying the keyboard in a bag and having it connected to a mobile device like your phone. The mod looks easy and I'll probably end up doing it myself, most people say it takes less than an hour.
It's not a perfect board but I'm liking it an awful lot. Amazon has the red switches version in stock here: https://www.amazon.com/Mechanical-Pro-Bluetooth-Backlight-Smartphone/dp/B06XW87X9D/ref=sr_1_5?ie=UTF8&qid=1498494412&sr=8-5&keywords=anne+pro+keyboard
Feel free to ask any questions if I missed anything.
EDIT: Just going to throw in a quick mention for CODE boards, as those are also highly rated and very popular for programming. They were the primary competition to the Anne Pro among keyboards I was looking at, and while I ended up not going with them they're a respectable company and may have something closer to the form factor that you're looking for, if that's an important enough concern for you.
It's a pretty solid little board, I like it a lot.