I guess its easier to hold such views on your side of the Atlantic than mine. America is separated from the Eurasian land mass by two large oceans. Life is a lot more complex in the Eurasian land mass. Everything is interconnected through trade, historical relationships, conflicting national interests and treaties.
Europe needs Russia as a stable neighbour. They have a long border with NATO and the western democracies and could cause a lot more trouble up to (and including) the next world war. There needs to be some sort of transition of power between regimes and not the sudden decaptiation of the Putin regime to maintain that stability.
I agree that China is a problem. China has already gained effective financial control of many countries , including resource rich ones in Africa. The land elements of Belt and Road makes the Stans part of their economic sphere of influence so they cannot be ignored. If the west is not economically and politically active in those areas we'll simply cede control of them to China and a weakened Russia. Kazakhstan is particularly important as its a buffer state between Russia and China, is supported by Russia, and is the launch site for the Russian space programme. Strategically we need a Russia capable of countering Chinese influence in the Stans, hence my opnions that post war Russia must remain stable, intact and credible as a world power.
I completely disagree with letting Syria burn. It borders Turkey which is a NATO country (but currently seems non-commital about this status). It borders Jordan, who have been a stabilising influence in the region. It borders Isreal, the only democracy in the region. It borders Iraq, whose oil resources and instability are well known. It's in a great locaton for expoerting problems to its neighbours. Mindul that Europe is reliant on the middle east for its oil, particularly if we're to abandon Russian oil, we need the establishment of stable governments in the middle east. If a weakened Russia withdraws from Syria we could see further instability in the country which could affect the flow of oil to western Europe. After decades of unstable governments, civil wars, international wars, ISIS and with a growing threat from Iran there is a desperate need for stability in the region, and I think the key to this is effective governments in Syria and Iraq.
Iran remains a major problem. The government is not Islamist in the traditional sense (that movement seems to based mainly in Sunni Islam) but its a Shi-ite theocracy. The Revolutionary Guard forms a state within a state and is far better funded and equipped than the national army. Unseating the regime will be messy, perhaps impossible. There are not many options for positive action against Iran without creating a whole new regional conflict as their Shi-ite support spreads into many countries in that region, not only the Arabic countries but also the Stans. Realistically the only option may be punitive sanctions while strengthening allies in the region, espcially Saudi Arabia. I think its a matter of containing the problem rather than solving it, and let internal tensions eventually bring down the government.