But if I use just Tor, then my ISP knows that I'm using Tor, which can be a much more problematic case, depends on where you live. If I use VPN + Tor, then the information of me using a Tor is forwarded from ISP to VPN, i.e. now VPN knows it instead of ISP.
I don't say that Tor alone is not safe, no, actually, You + Tor is the safest option but what I'm saying is that I'm afraid the fact that you use Tor, for the government, automatically means that you are doing something wrong and are already in their watchlist. That's why I would move towards VPN + Tor combo, definitely if everything is done correctly. But still it's a trust business.
Innocent until proven guilty. Are you doing something illegal? If you are, then there is no point hiding anything so long as you can protect your privacy properly using Tor. They cannot legally prosecute you without sufficient information, and if done correctly, landing on their watchlist does nothing to you.
On the contrary, there are many ways that you can land on their watchlist and using Tor is probably an insignificant part of it. If they want to monitor you, they would pounce at every chance that they can get. Using a VPN in this case provides you with a false sense of security.
If you are confident that you can ensure that your VPN isn't already a honeypot, and you can effectively prevent any leakage of information, then go ahead. It would still be possible to conduct traffic analysis to come to the conclusion that you're still running Tor.
At the end of the day, you can certainly do so with marginal improvement on your privacy. That is assuming you know how to prevent any VPN leakage and configure Tor to work properly before considering the even slower synchronization.