So my server is spammed every 5 seconds and it pisses me off, I even tried to put useSSL: false and verifyServerCertificate: false at properties settings and even after the database: database: luckperms?useSSL=false&verifyServerCertificate=false

I have the latest version available: LuckPerms-Bungee-4.4.26

Can't I fix it somehow?

04:27:08 [SEVERE] Thu Jun 27 04:27:08 GMT-03:00 2019 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.

Please check the wiki next time:
https://github.com/lucko/LuckPerms/wiki/Storage-system-errors#mysql-ssl-errors

If you get an error similar to:

Establishing SSL connection without server's identity verification is not recommended. According to MySQL requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.

... you need to disable SSL for MySQL connections.

You can do this by editing the connection properties in the LuckPerms config file. Under the "Storage" section, locate:

data:
  pool-settings:
    # This setting allows you to define extra properties for connections.
    properties:
      useUnicode: true
      characterEncoding: utf8
      useSSL: false
      verifyServerCertificate: false

and add the last two options.

You have to manually add the options in the LP config under the section shown above.

I added them like I said in my previous comment but still getting errors..

Can you provide a copy of your config through https://hastebin.com please?
Make sure to remove username and password in the database settings

Link

Seems fine...
I'm out of ideas and can't help any further... So you have to wait for @lucko to answer with possible solutions/reasons.

Well, the error was from another plugin, thanks for helping me out! :))

The thing is if you are using the same database server for several plugins, most likely all of them will throw the same error/warning.