I quite enjoy this game, but it does have some ups and downs.
If you want to grind effectively you must buy premium time, that is basically your only chance to getting to jets quickly.
I am only a level 56, so take my advice with a grain of salt.
I am above average in some planes, and I have my fair share of time in tanks too.
One thing you will notice if you first get into war thunder, is that all the new stuff is at top tier, which will take a long while to get too. And even if you do, (I only have 8.0 German jets and 8.3 swift, 7.7 Sweden ground forces, 6.3 american ground forces, 6.3 German ground forces, 4.3 USSR ground forces) they might not be as fun as 5.7 and below.
In ground forces, you have to deal with a thing called repair cost, which makes you lose the in game currency if you don't do enough for your team, or if the repair cost is tooooo high. That is what stopped me from continuing to play 7.7. I find that once you hit jets, you find that playing lower tier 4.3 or 5.7 props is more enjoyable.
Also, it takes twice as long to grind ground forces, as the amount of research points you get is cut in half from what you would get from playing in planes.
But other than that, it is a very realistic game, but very rage inducing. Fun to play for me, but that is because I am killing lots of people and making it unfun for others. I wouldn't advise you buying into top tier, because the people up there are probably better than you, so don't waste your money on that unless you are already in top tier.
Oh and also, I mainly play rb