Hi Guys
Thanks in advance.

I am new here

As my subject title suggest I guess what I am going to ask all here, you have heard all before and maybe deep in the depths of previous questions and responses the answers maybe their. But this is part of the reason I am asking what I am asking. I seem to be getting nowhere fast, despite searching the web for various things and finding conflicting answers.
If SEO expertise is on a scale of 1-10, with 10 being a super duper expert then I would say I am maybe a 3 so not a newbie, newbie, but totally confused. Okay enough already let's get to it
I have created a website myself using WordPress and use a popular SEO plugin. I have carried out some keyword research and followed the requirements of the plugin with respect to SEO and Meta description displays. All seemed good to go, However..
1. Many of my pages don't seem to be indexed in Google despite requested Google fetch to index them. Yandex is the same?? Not sure why on earth that could be
2. Many of my SEO titles seem to have my brand name attached to the end of my SEO title thus not displaying properly in Google.
3. My meta description in some cases does not exist at all but text from my page replaces it? I look at the 'character' length also how many would you say is correct without spaces? There is such a difference on the web as to the correct number.
4. The Same for the SEO title 'character' length also how many would you say is correct without spaces?
Both SEO title and Meta description all seems a bit of a mess.
Having what I thought (based on the plugin response) 'no errors' on my site. I started to look further into the programs that provide a fuller picture of your site. The Arefs, Semrush and SE rankings of this world type of software. Again a minefield any suggestions on which one you guys suggest here as there are so many and Soooooooooo expensive for a startup like me. Anyways, I started a free trial and have had returned hundreds of errors 5 or 6 critical like site maps which my original plugin submits? but many many many on character length for SEO and Meta descriptions, which according to my plugin are correct.
Sorry to go on but hopefully you can see my dilemma, so any advice on
Meta descriptions & SEO title character length would be great
Why are meta descriptions being substituted?
Why is my brand name being added to the Seo Title
Which software would you recommend to use to bring all the website information together using companies like Arefs, Semrush and SE rankings types of service they provide at reasonable cost, any free ones?
Thanks again in advance
A Confused Limpopoboy ...