Is Oracle 18c XE good enough to start learning to be a DBA? I don't know if the esteemed community here will find this question silly, but at the same time I thought that I would get a good answer to my question here.

As of now, I am into writing SQL queries/procedures, etc(dev work).
Additionally, in future I also plan to gain knowledge on DBA tasks(at least the basic ones).

I know that each DB is greatly different from another, but I would like to know which one is the easiest DB to learn DBA tasks.
By easiness I mean, I can install it on my PC and learn them without having to go to a school for training(As I lack time to do so).

Oracle is said to be the most widely used relation DB, but will Oracle 18c XE enable me to learn and perform basic DBA tasks(for DBs 12c and above)?

Another DB that I have on my radar is MySQL, if so, will installing the community edition help me learn things, Or do I have to go for the enterprise one?
The "First Commandment" of any DBA is: Thou Shall Not Lose Data!

To accomplish this, you'll want to teardown, build, and restore/recover the database multiple times.  To that end, I'd recommend you use some sort of virtualization (eg Oracle VirtualBox).

You might be able to find both Oracle EE and MySQL pre-made virtual guests for VirtualBox.

I believe RMAN on XE is limited.  So, for backup/recovery practicing, I'd use EE.

Beyond that, any edition (of any RDBMS) would do.