I totally empathise with you newb – and this was from someone who had six years of strata under their belt to move into a complex multi-strata development with issues up to its eyeballs. I appreciate and admire your enthusiasm and conscientiousness.
I agree though with Jimmy and others. Unfortunately, I too ruffled feathers through letter writing about finances, insurance and the upkeep of common property which got me nowhere fast. There were $100K+ in overdue levies that were not being followed up by the strata manager. Illicit drug transactions on common property. All sorts of things.
What it took was some patience. Firstly, once I realised I had gone in guns blazing, I sat back and kept myself to myself. These things have a habit of settling down if you go silent for a while, a few months at least. You have ruffled feathers but maybe, just maybe, some on the committee have heard your messages and some of it will sink in over time. Say hello to them as you see them, make small talk, be interested in their dogs, whatever it takes. Just become known as someone constructive who is not out to make trouble. Help them realise that you are someone they want on the committee.
Once you have established some rep, then you can begin to dial things up in a respectful manner. Baby steps at first. Just pick one or two issues and build up your knowledge, make some phone calls yourself to get quotes, go out take pictures of other complexes as might help (I did this when looking at new security systems and signage). No more letter writing or emails or badgering the committee over everything. For the finances, the best way I found to address it was to ask politely at the AGM for a financial auditor to review the accounts (as often as recommended by your SM). It is a pretty weak control to be honest, but it could cause your committee and SM to reflect on their actions. It is a subtle way to bring finances into the fore.
Then you can also volunteer to help the committee with various things that take almost zero effort. For example, if a tradesperson is coming early one morning, you could volunteer to let them into the building or show them where work is required. You become someone they can trust and rely upon. Then over time catalogue issues in the place, things you have found in your travels, and raise them informally with some suggestions. Form a bit of a working group to work through the list and prioritise. It may be some things are on a maintenance plan eventually. But other things might be small potatoes that you can sort out yourselves.
In short, I wish you the very best of luck. Subtlety is key. Once you make your inroads, then you can start to respectfully disrupt things. You will then be seen as a trusted, reliable and constructive community member.