Depends on the time and place... Greece for example was fairly open, but you might find yourself dead for exposing the secrets of the mystery schools. If not that you have the issue of building up a number of technologies and spreading them enough which you probably couldn't do.

Rome had knowledge of up to around the 1930s level tech. They just didn't use it or it was blocked by imperial decree.

European Kingdoms would back you so long as you got results. The catholic church was more against wide spread knowledge that contradicted them, not inventings stuff.

Some of the US colonies you'd be able to advance very quickly, while others would burn you at the stake.

Asia in general you would end up in a lavish prison with everything paid for. You might be free to roam the town or travel, but you'd be under constant guard and all your work would go towards 1 lord or another. You'd be pretty safe and free otherwise save for the possible assassination attempts from other lords, but other than that you'd be fine.

The Golden Horde might be a problem only due to their policy of killing betrayers and so if you were working somewhere and they conquored it they might view it as you betraying that village/town and might kill you.

Arabia you'd never get what you need to really advance, even in the most lavish of surrounding you'd never get anywhere worth while to even remotely be considered "magic"

So... In most parts of the world and time you'd mostly be perfectly safe. The main problem is standard political moves that you'd find yourself in danger from.

Depends on the time and place... Greece for example was fairly open, but you might find yourself dead for exposing the secrets of the mystery schools. If not that you have the issue of building up a number of technologies and spreading them enough which you probably couldn't do.

Rome had knowledge of up to around the 1930s level tech. They just didn't use it or it was blocked by imperial decree.

European Kingdoms would back you so long as you got results. The catholic church was more against wide spread knowledge that contradicted them, not inventings stuff.

Some of the US colonies you'd be able to advance very quickly, while others would burn you at the stake.

Asia in general you would end up in a lavish prison with everything paid for. You might be free to roam the town or travel, but you'd be under constant guard and all your work would go towards 1 lord or another. You'd be pretty safe and free otherwise save for the possible assassination attempts from other lords, but other than that you'd be fine.

The Golden Horde might be a problem only due to their policy of killing betrayers and so if you were working somewhere and they conquored it they might view it as you betraying that village/town and might kill you.

Arabia you'd never get what you need to really advance, even in the most lavish of surrounding you'd never get anywhere worth while to even remotely be considered "magic"

So... In most parts of the world and time you'd mostly be perfectly safe. The main problem is standard political moves that you'd find yourself in danger from.

Also, as someone with the knowledge and intellect to build a society and it's technology practically from the ground up to present day levels the main issue other than politics is skill and money. The majority of people, no matter what their level of knowledge is on particular subject, cannot produce the level of skill necessary for creating components for one of these technologies let alone all of them. The best you could do is create a cabal of people work with and teach them the practical aspects of things and then also write down all the theory about things. doing that, you might get to just before modern tech in a life time from Agrarian levels of technology. Noone has enough knowledge to get modern tech because it requires to many specialties and infrastructure to work.