Beginners Questions regarding Gameplay

Hello everyone,
I've been intrested in Aviaton and the technical Workingprincipals of Airplanes and ATC for ages, but I am a newbie to the whole Flightsimulation-world. I recently got myself the FSX Steam-Edition and started playing around in Missions and Free Flight. I know how to get airbourne and eventhough I'm still struggeling with the navigation a bit most of the times landings work out ok. I wanted to start playing multiplayer and tried with the Steam-Servers but most of the times they are just very random gameplay with planes crashing everywhere and no real ATC-Communicatons. I wanted to switch to some more realistic Servers via Direct Connect but I couldn't get it to Work and someone on the TeamSpeak of that Server told me that most of the good Servers could not be connected to with Steam-Edition to keep out Players that aren't seriuos about the Game.

My Questions:
1. Is that true that FSX:SE cant connect to Boxed-Version Servers or is my Setup just not right?
2. If it is possible to Connect to Boxed-Version Severs what might be my Problem?
3. If it is true and I can't enter those more realistic Servers, what would be the best Option of the Boxed-Versions to buy if I intend to play realistic and also wanna try out playing ATC, the description of the different Versions is very vague.

Sorry for those newbie-questions
kind regards
 

Check this thread out.
https://steamcommunity.com/app/314160/discussions/1/617328415068748883/

Also try  www.vatsim.net
If you want to buy a boxed version of FSX get the Gold version (best).
It contains both patches built in and also has the Acceleration Pack built in.
Maybe you can find it on ebay, your call.

https://www.amazon.com/Microsoft-Flight-Simulator-X-Gold-PC/dp/B001DPZE84/ref=pd_sbs_63_img_1/144-0813648-0998244?_encoding=UTF8&pd_rd_i=B001DPZE84&pd_rd_r=febec457-dea6-4660-acd1-32bcf9a5bf6c&pd_rd_w=vMlef&pd_rd_wg=zvyHM&pf_rd_p=5cfcfe89-300f-47d2-b1ad-a4e27203a02a&pf_rd_r=8KPGM7YGPEDM63AXZ2D2&psc=1&refRID=8KPGM7YGPEDM63AXZ2D2