Look at the options here:
Thanks! From what I can see its mostly battery powered switches. Sadly this is not an option since I want to get rid of the smart bulbs. There is one solution that looks interesting " Zigbee Coupler" it looks like a very flat relay that might fit behind the switch but not sure. Ill look further and see what I can find. Ideally I can find a dimmer and non-dimmer switch that fits into the existing frames and is a Zigbee router on top 
Edit: the above one is also battery powered.
@jeleniain , I never found anything (except the LK Wiser series; the ones you mentioned).
Anything that actually connects to the mains won’t fit in the slim Danish standard switch boxes. I’ve tried quite a few of the smallest I could find on the Danish, Chinese and US markets.
One option I considered was to make a 2x switch box (this size for a single switch), and just “blind” one part with this so it’s not in use, just supplying extra space in the box/wall. As I see it, when there’s nothing inside (i.e., no wires the need to connect behind), one of these or these might just fit in a 1x1 standard Danish wall switch. Bit as soon as you need a functional switch on top, it won’t fit (I’ve tried, as much as I dared, to force it in).
However [caveat], since we were done with the electrician and had everything looking nice and pretty before I realized this, I haven’t tried. If you do, let me know if it works, for future reference 
I stumbled over some Nordtronic devices o. lavprisel.dk the other day.
Try to search for “nordtronic zigbee” on their site.
Unfortunately, it’s the exact same dimensions (45x45x20.3 mm) as the ones I linked to in the last post. I have several of those, and can’t make them fit, even with moderate force.
@Aephir thanks! I was thinking to try something similar with the 2 switch box. I just got myself a Sonoff extreme relay which ich think is the smallest one on the market yet but even that wont fit At this point I am close to give up. The only “problem” is that some of my outdoor lamps do have a g23 two pin socket and I would love to make them smart. The Wiser series is just sooo expensive I to put into the whole house. I was thinking how many laws I would break if I take a concrete drill and you know, drill into the concrete through the AIR dåser and make some extra space in there 
as far as I can tell there is only concrete but I also dont want to loose my insurance cover for my house just so I can satisfy my smart home needs hehe. Either way, I will keep you posted If I figure out what to do. Thanks for getting back to me!
A bit late, I know, but if there’s enough room in the bulb housing, you could consider just adding an adapter (e.g., like this G23 to E27), they’re DKK 23, so won’t break the bank. Then just use a “normal” smart bulb and not void your insurance?
As a side note, I just had one of the two-way LG Wiser switches installed. They work really well, but as you say, it would be kind of pricey to do that for 25 switches throughout the house.
One drawback with both the LG Wiser and all the small-ish (45.5 x 45 x 20.3 mm) modules I have tried is that they all make a loud annoying “click” sound when toggled, also by remote (I know, I know, so does an old fashioned switch. But after being used to Zigbee bulbs, it seems a bit dated and backwards).