domain name? nonsense? subdomain? - tech site

Im developing a website which targets all about consumer electronics and some tech stuff.
Basically I want to build an authority site or network imperium that covers the whole electronics topic. Yeah sounds big task but I take massive action 10 hours a day and articles are flowing easily out of my head.
+ its not in english language.

I would love to have all in one site as this would help me manage it much easier so I tend to one domain name.

Prob is that all tech/electronic stuff names are gone. Even the most idiotic mixwords.
Now I started to create words out of latin meanings. I have some I like and which could be associated with tech stuff but are still nonsense words kind of. I like a short nonsense word more then some 12 letter domain with 3 stuffed keywords cause every 2 word combo is gone
I do want to rank for the long tails of the various tech niches(at first). Applying siloing and lsi.

Now does it make sense to structure my site this way?:

etc. ..
all sudomains are linked from ww, nonsensemixword ,co and inbetween the subdomains whenever I find some connection.

would I rank this way for *techniche* and *technichelongtail*?
would google recognize that it is about the subdomain and not about the nonsensemixword domain? Or do I get a penalty for using a domain that makes no sense?
would be nice to have a brand where people say "oh nonsensemixword , co got that right lets check again for technichexxx"

had to cripple domain names cause of board restrict.

btw. first post HI! :p