i know that it's a stupid question but i was asking if i could play with dlcs or with romanian content
You can do both, it's not mutually exclusive. Sure, a large collection has its downsides, but even then you can have two installations. I suppose the thought behind the question is, DLCs are supposedly stable while the content of your heart's desire requires quite some effort to get working. Just do whatever you fancy in a given moment.
You can run what you want If you like Romanian trains then run them - if you like other countries run those - mix them if you want.