I always found that setting up the first aquarium was the hardest, especially with regards to the waiting.
Once that's up and running, the second...and third...and fourth...etc., get easier and easier.
If nothing else, you should have access to a good supply of beneficial bacterium.
MTS isn't an addiction in the clinical sense...though it can easily become a symptom of an obsession.
Lol, I have 13 tanks (had) and just set up 4 more. They are 5.5 gallons, but now we have 17 tanks set up. 18 if you count my box turtle's water feature that has guppies and killifish.
I have been mucking around for around 45 years with fish, and have always had some in that time. At the moment I only have my pond. But I have a 6 Foot and 4 Foot tank plus 4 others, Just waiting for me to decide what I will do next.