This is a big thing I've been working on recently. Reducing the amount of UI on screen but keeping everything within reach.
After my consultation with Esty, he explained how overwhelming the game was on a first playthrough. There were just too many buttons and words and things going on at once. Since I've been using this UI and built it myself, I'm very accustomed to knowing where everything is, but for a brand new player they're going to have to look for what they want to do. There's a lot of ways to guide the player using colors, positioning, and size of buttons.

An old version of the custom lobby

Looking at this there's way too much to look at, way too many words on the screen especially with the decklists. Dreadwyrm on the left has a deck of 12 spells, so even something like reducing deck size actually helps here.

This is the local game mode, but you can see there are no scrollbars on the decklists now. Changing the header buttons to icon buttons makes a huge difference in how cluttered the screen feels. I initially really disliked when Valorant changed their header buttons from text to icons, and didn't understand why until I realized I wanted to declutter my own game's ui. There are many more changes that went towards reducing ui, including having a toggle for showing advanced options in training mode, and removing the mana regen markers during normal battles.
There's a lot that goes in to making sure a new player feels comfortable enough to return to the game, but it's not talked about much. Though Ben Brode did a GDC talk about designing Marvel Snap, and one of his points was not ever having more than "8 words on screen at any given time." This is extremely difficult to stick to.

But using it as a guideline can make a huge difference.