No, such groups do not exist here, sorry. Perhaps chiefly because this is the forum for Magix products and at least some of your "topics" are not directly related to those products and would, perhaps, be considered peripheral to them. However, there is nothing to stop you asking specific questions about any or all of your topics in this Off Topic forum, but I honestly have no idea how many, if any, users who visit and post here would be able to help you and so respond.
On the whole, therefore, I think that yes, you would be better off finding sites that are specifically and more narrowly targeted at those type of things. I will freely admit I have no recommendations of any such sites, save to say to beware of any that attempt to preach that theirs can supply ALL the information you are ever going to need!!!
If you have specific questions you can post, them in the Video Editing section if you wish for more responders (others have in the past) Just make it editing related if you can. So you could ask something like 'what is the best way to stop my videos shaking? or similar. Then we could reply 'Bu using a plugin of XXX or suggest a shooting tip.
Another option would be to contact a member by personal message. (You can find that link in your personal area.)
Some of us would be willing to give our opinions or personal experiences which will vary. So for instance it would be no good asking me about lighting rigs. I have never used any but cameras, yes, shooting techniques and general camera settings, most of the time, Audio definitely a yes. Sound treatment, yes. Depends how deep down the rabbit hole you want to go. Just remember it can get very expensive very quickly. Cheap normally means compromise and although it may work at first, as you get better and more demanding you may get and end up paying several times over for a better version of the same thing.
John, EB taught photography for a while and I was in the film and TV / radio technical side of things in my younger days. Mainly involved in the audio side of things. Things have changed a lot for both of us since then technically but we do our best to keep up.
I think Stephen above has had a lot of DAW experience but at what level I'm not sure.