Lately I have just finished Problems with Philosophy by Bertrand Russel, a pretty simple book for the public and my first dive into Russel's theories. After this I started A Treaties Concerning the Principles of Human Knowledge by George Berkeley. It struck me how different their views were and yet how sound their arguments are. This was also my first time reading any Berkeley. So I was wondering if anyone had opinions on the difference between rationalism and idealism? And how each of these men portray it? Because if I remember right Russel does seem to criticize Berkeley a little bit in his book. Berkeley being an extreme idealist, and Russel being very rational.

Also if you have any recommendations for books or philosophers I should look into I would love it!

Albert Einstein has a short essay titled "the world as I see it". It is extremely beautiful, and I find it to be extremely valuable simply because of the intellectual respect Einstein possesses culturally.

Foremost, there's different strands of philosophical idealism. I'd suggest looking into Kant, Hegel, Schopenhauer, F.H. Bradley, and Berkeley, as you've noted. I will update this post later with some texts regarding the idealist schools of thought.

Some works which might be helpful in further understanding idealism (Subjective, Objective, Absolute, Transcendental):

The Critique of Pure Reason, by Immanuel Kant
Kant's Transcendental Idealism: An Interpretation and Defense, by Henry E. Allison
Phenomenology of Spirit, by G.W.F. Hegel
Hegel's Idealism: The Satisfactions of Self-Consciousness, by Robert B. Pippin
German Philosophy 1760-1860: The Legacy of Idealism, by Terry P. Pinkard
The World and the Individual, by Josiah Royce
Appearance and Reality: A Metaphysical Essay, by F. H. Bradley
Idealism: The History of a Philosophy, by Jeremy Dunham, Iain Hamilton Grant, and Sean Watson (A book I'm going to purchase soon; I'm presuming it's going to be a comprehensive work encompassing all of the varieties of idealism).

Also, give this short story of philosophical fiction a read: "Tlön, Uqbar, Orbis Tertius," by Jorge Luis Borges. I found it to be demonstrative of subjective idealism.

For further comprehension of rationalist thought, give The Rationalists and Understanding Rationalism a read.

Thank you both of you I'm still pretty new to philosophy but I enjoy it deeply, again thank you both for the recommendations I will have a lot of reading on my hands soon!

I have read some stuff concerning the ideas of Kant and Hegel both of which I found interesting, Kant was a little more hard to grasp. But I did find Hegel's ideas very intriguing.