There were two things that bothered me more than they should, and i now found workarounds for them.
1: Whenever i booted up my local srcds (This is for windows) it took like 3-4 seconds before it even started doing anything. A message briefly appeared saying "Timed out waiting for game mapping!" and then it finally started booting up.
Fix: In the same folder as the srcds.exe, edit the steam_appid.txt. In my case i just entered 845 (which seems to be invalid, but whatever). Save the file, revoke write and change permissions to the file as srcds will (try to) overwrite it to the correct appid again. Srcds now does not have this "freeze period" in the beginning anymore
2: Starting srcds caused Steam to detect me playing CS:GO, forcing me to start CS:GO before starting the server because otherwise i cannot start the client.
Fix (Or workaround rather): In the csgo folder find the file steam.inf. Edit it and change the appid to something different, 845 again in my case and save it. Do not make this one writeprotected as srcds pulls its current version from this file (and will obviously have to update it when you update the server).
Boom, steam does not detect you playing CS anymore when you start the server.
Side-effect: Whenever connecting to the server a message will be logged, stating that the client connected with a ticked for the wrong game. So, the client will not authorize and not get assigned his Steam-id. For me this is no problem as its a local server anyways, this is caused by the latter trick, so feel free to do that, or not. The first one does not have any side-effects.
If you should know a better fix for this feel free to contribute