There's actually a very popular and hyper-realistic military simulator called Command: Modern operations. It's so good that the US naval academy uses it to wargame scenarios.

It only allows you to control air and naval assets. One scenario was a Russian invasion of Ukraine in 2016.

Now mind you, I played this scenario with a lot of handicaps compared to the real-life scenario today. Like:

1. This was set back in 2016 when Russia hadn't completed its modernization and didn't have as many Iskander missiles, few Su-35s and Su-34s, a handful of active guidance air-to-air missiles, and a less-developed missile arsenal.

2. I was not allowed to use any ground assets, meaning I couldn't make use of Russia's enormous artillery arsenal which is arguably the most powerful in the world.

3. It modeled NATO as providing an active and immediate response with aircraft making sorties from Turkey, Poland, and Hungary. Plus, there were multiple NATO frigates in the black sea.

4. I was not well versed in the game's mechanics. I had trouble manually limiting bomb and missile usage on individual targets, so I had to rely on automatic fire more.

The results were in less than 2 days of fighting:

1. I destroyed the entire Ukrainian airforce. Destroyed one of their major airbases and crippled another two.

2. I destroyed all Ukrainian ground-based air defense systems and all their radar installations.

3. I destroyed the NATO AEGIS ballistic missile defense system in Romania.

4. I destroyed 4 NATO warships and destroyed 40 NATO aircraft.

5. I destroyed over 160 Ukrainian tanks and artillery pieces just through air power alone.

The only serious losses I suffered were in the Crimean sector owing to its isolation from the Russian mainland. And I did this with just the forces allocated to the Russian southern military district.

In contrast, in 2021, the Russian air and naval force is much stronger than before. And the Southern MD has been greatly reinforced.