I have been in the financial services industry for about 15 years and my sense is that power dynamics in most organizations drives decision making, as opposed to analytical insights.
That also means that while financial analysts can actually make meaningful changes through insights, very few organizations understand that and hence they value those who solve more clear and present business challenges (like sourcing business or funds) than those who are in analytical roles. Unfortunately, most analysts are seen as cost centers in organizations instead of value creation centers.
So, its critical that you pick your target organization well, and keep looking until you find ones that value strategic insights derived from data.
The answer to "how exactly to use spreadsheets and tools" - can be simple - as long as you understand the basics of mathematics / statistics and accounting (in that order, in my opinion) , and can think logically, the best way is to start messing with assignments / case studies / tasks until you build enough intuition of what to do. That said, I can vouch for the fact that new assignments can still surprise you with their novelty/complexity at times, even after working for 15 years. Although luckily LLMs are emerging as a good tool to deal with such new projects by bouncing ideas off of them, and to get broad understanding of new things instead of reading books or googling.