Strange characters in database and how to make them readable

[Inna]

Hi, my database charset and all the vBulletin charsets are "latin1_swedish_ci".
In some tables like username or posts, I see characters that are strange to me, but are readable by the server to convert them to the correct letters. Like this
سعید
This is in Persian "سعید".
I tried changing all tables and vb database to utf8_persian_ci, and also ut8mb4_persian_ci and ut88_general_ci, and I changed the collation of all tables to these, but nothing converted.
How can I fix this? Both for the existing data and the future data.

[Dave]

Did you change the character set doing https://stackoverflow.com/a/6115705/6275228 ?

[Inna]

Yes, I have, but that didn't work.

[snakes1100]

Is it a plesk server, if so, plesk has a nasty issue of setting a local php.ini with a charset entry & its forces sql to use UTF8.

[Inna]

No, it's DirectAdmin.