Specific niche or more broad niche?

Ok guys my english is not the best but ill try...

The thing is I'm a lawyer, and in my country most of the lawyers job is presential, meeting the client, getting the job, go to court, appeal and finally get paid or split the profits...

But there are some very specific cases you can do online, there is no need to go in person to the court, things like:
1. Small civil cases against online stores
2. Write contracts
3. Help in administratives jobs like apply for retirement or appeal in traffic or sanitary violations.
and others...

Ok some of those are very tiny and specific niches that I'm getting a hard time to figure out enough content to produce one site.
After some research I found some guy saying google is ranking higher the bigger sites... So 1 unique site with 100 posts would be better than 5 sites with 20 posts each.

So the idea is to make like a bigger site with all the topics inside, each one with a different convertion page like "Leave your email for a free consultation..."

After all... 1 big site alltogether or 3-5 smaller sites?

One big, authoritative site is much better than a few smaller sites especially in such a niche market like yours. Which is I assume is legal advice specific to one country.

All those specific cases could be its own category within a larger domain. Say the domain would be for example <country>legaladvice.com or something like that. And all specific cases like civil cases, handling violations or writing your own contracts would be the categories within that one site.

It's much harder to maintain 5 sites vs 1. Easier to rank your pages with just one site, especially if it's such a niche topic.

At first try to narrow your niche, I mean, at first work sub niche, Then move to broad niche

Thank you all.
I'm really having a hard time deciding the right path, going to research a little bit more..

There's really no right or wrong answer here, but since you’re just getting started, it’s best to focus on one bigger site, rather than on 2-3 smaller ones. You’ll end up getting overwhelmed if you try to maintain several websites at once, and you’ll inevitably end up neglecting at least one of them.