This is one isekai where the MC actually had time to prepare. Almost all don't. And vast majority of people are rarely experts enough in both a field and all the upstream fields to introduce a full technology stack (not just material acquisition, but also need how to make tools to make more tools to make more tools etc etc). Release That Witch did have to asspull a bit to get the MC to have enough breadth of knowledge to introduce so much industry in that kingdom builder isekai (basically, about 1/3 of the way, added effectively perfect recall, and then later, effectively humanity's Akashic Records).
As mentioned, MC definitely should've at least downloaded Wikipedia. If only because he may try to remember something and that would help, even if he hadn't planned on aggressively using it. That's not enough for actually producing very many technologies, but it would at least cover the overall ideas of most things.
For specifics, he really would've had to dug in and do research on what how-to's he would need, and there's no way he would've been able to download enough videos to cover everything. Certainly could've hit the main technologies for uplifting a middle age civilization... and he should've taken like a couple of hours of Aura's/advisor's time in the first day, rather than waste time sleeping (he was only there for like 24hrs, tough it out), to get a debrief on everything about the world that he could get crammed in/take notes on to see where some likely easy improvements could be made (steel making [basics to industrial scale], tool schematics, printing press, paper, farming, chemistry, economics... games, music & instruments, painting, philosophy, I'm sure many, many others). Even if he didn't intend on using it, he should've thought it might come up in the next 10-30 years and he would have some preparation for such an occasion.
He both had a whole month and yet only had a month. Definitely could've put some better effort in.