[PLEASE HELP] My fears towards spending in Google Adwords

Hello guys, I'm requesting for your help, please debunk or confirm the myths in my mind regarding google ads that stop me from trying it out.

Firstly a few background of my little experience, I have a business for 3 years already, it is a brick and mortar shop that is doing really well especially in ranking in the first page of google for the keywords that matter most for us. We have very good walk in rates from people that say they've found us on the internet and believes in our services as we got generally good reviews over the internet. I've worked to get to this position very hard from making the website on my own, doing some basic and a little complex SEO, getting our shop verified, making sure of posting quality content etc... I believe my efforts got our business to the 1st 2nd and 3rd in the search rankings and also in also rank very well in the google maps listing in our respective chosen keywords. We are relatively ranked well also in other sites especially in Facebook... ( I spent a lot already in Facebook advertisements for my business and for other businesses as well that I can say I am quite familiar with the platform already) However, I've never spent a dime on google ads because of the following fears. But given the resources available I believe I can handle it)

The myths/fears I believe:

1.) I am afraid that if I spend money on google ads... our 4.8 google map listing will be pestered by trolls or competitors who wishes nothing but the worst for us. Dropping irrelevant or unfair reviews which could really affect our reputation. (since we are reliant on our reputation online, where many customers come to our shop because of the reviews. I'm afraid this will hurt it)

2.) Our organic search engine rankings will be altered after stopping with the ads. (I'm afraid that Google's algorithms favors those who are popular organically, hence if we spend ads they will classify us as someone who became popular because of ads so they might drop our rankings if we stop). I will be sad if we rank lower or worst go to the 2nd page.

3.) Our organic reach for our listing will go down...(as of the moment we get around 50k organic views per month which in my limited knowledge believes to be quite a lot already since we haven't spent a dime on google ads) I'm afraid if I stop... our organic views will be sliced to 2/3 or something since they would want us to spend more.

4.) I am afraid that if I spend money on a certain keyword, I'd drop in relevance score in other keywords and just streamline in one (say if I spent on the keyword Chocolate Cupcakes, I'd rank lower in my other keywords which is equally useful and converting... let's say bakery in Ohio *this is just an example*).