What is better to choose for maintaining a customer base - a ready-made engine or self-writing?

Question

CMS

Good afternoon!
There is a charitable organization, a branch of the Red Cross.
There are 5 branches of the organization in the city. Each organization has 2-3 CRM users who add new ones to the database. The reason is standard - now there is only one organization, and everyone has their own bases. So they are worn
When entering the system, it should be possible to select "Add client", "View database", "Search".
"Add client".
The database contains standard fields for each visitor: dossier number (should generate +1 to the previous one), age, name, language, number of children, and 3-5 more columns. If the client has children, a wife/husband, then they are also added to the database and linked to the first applicant (client). When you open a child's card, you can see the whole family.
You also need to upload several files (pdf, doc, jpg).
"View base"
Each branch has the right to see only its customers with the ability to search. Ability to filter and export to Excel.
The auditor has the rights to see everyone (with the ability to export everyone to Excel).
"Search"
Instant search for a client (by the first letters entered in the field Name, Surname). Separate search by dossier number. When choosing a client, it is possible to edit his card.
And now a question-suggestion: what is the best way to make such a CRM - on MODX Revo (I would very much like to choose this particular framework) or do it from scratch?
CRM for internal use only, will be located on our own domain in a separate directory.
Who is ready to implement this - wellcome in a personal. We will negotiate.

Answer 1

Thanks everyone for the replies.
For this organization, the CiviCRM system was suitable https://civicrm.org/
This system is for schools, associations, churches, public organizations. It is installed as a module on Drupal (other engines are also possible).

Answer 2

1. Self-writing does not need to be done in principle. If you need to dig up a couple of potato bushes, you don’t row with your hands because a shovel is redundant.
2. TK for CRM is never complete, therefore - it's better to lay hay in advance and write on a framework, for example, on Yii2, or Laravel
3. Version control system, for example git - MANDATORY!

Answer 3

If you choose MODX, then Revo is better.
Evolution is deprecated.

Answer 4

I can do it on yii2 or from scratch. skype if interested

Answer 5

I would choose self-writing, the functionality of the engine is redundant for such

Answer 6

I would suggest to start with a little analysis of online CRM. Spend a couple of hours on this, but, if successful, you will get the finished thing in half an hour of registration and settings.
If you do not find a suitable option, then you will understand much better not only what is needed, but also what is not needed, superfluous, will interfere. Consequently, the TOR for the development will be more complete and specific.

Answer 7

We eventually chose WP - pm which is the absolute world leader. Most of all ready-made components, solutions, articles, specialists. Easier to solve problems.
And in the end it turned out this systemo.biz/casepress
As a result, it was possible to introduce CRM analogues in terms of covering the number of business processes, data slice, reports, and the number of employees within one platform - there are simply no in the Russian Federation.