I suspect there are as many “ideal specifications” for a MSFS PC as there are users on this forum! 
Seriously, have a look at this thread, though I think these are US dollars:
That build is more than your budget, but you could use it a starting point and perhaps save some $$ on the case, purchase a 2TB SSD (I’d not recommend a HDD any more other than for archiving purposes), or purchase a lower-rated power supply, depending on the requirements of your chosen CPU & GPU.
W.r.t. the best graphics card, I have an Intel Arc A770 & am happy with it, but there are better (& more expensive) cards from AMD & NVidia. My only recommendation here is that whatever card you purchase has at least 16 GB onboard RAM.
Another post to peruse that might help is here. And a search for “optimal PC build” will bring up many more posts for your consideration.