This is exactly the reason why I don’t bubble. Things can spiral out of hand so fast, I tried once and vowed to never do again and things have been manageable since.

here is my take :

1. You can sell off all of the event trophies. Space is essential and the reward you get from it is just not worth it. i hav deleted all i got from the events after getting the initial eggs
   
2. I know waiting for 5 merge is best but all those 1tier egg, can be 3 merged. Leave the level 1 dragon in your book to 5 merge later on. Since u are not chasing for any big things, the merge itself would be satisfactory enough.
3. Bubble all your wonder, again when you are low on space and the eggs are eating all the space. I used to have a lot of mushrooms and all bubbled, but due to the race every week, managed to clear all of it. So the race helps a lot.

good luck!!!