For me, it depends on the symbols and how they’re used. I think the PF2 action symbols are fine. They’re simple and map intuitively to how many actions you need (one diamond = one action, two = two actions, etc). The icons used for monster powers in 4e? No. They make the layout messy and are sometimes redundant.TBH, I kind of hate it when RPGs use color and/or symbol coding. My brain jsst doesn't seem to be wired to remember things in relation to colours or symbols. I never know what any of them mean and immediately feel overwhelmed by them. It's one of the reasons I gave up on Warhammer 4.
For example, consider the Angel of Battle (because it’s in the MM sample on DM’s Guild). It has the following powers: Falchion, Mobile Melee Attack, Storm of Blades, and Chosen Foe. In the stat block, there is plenty of space to include type (“basic melee attack”, “melee attack”, “close burst”) along with each power’s action and recharge. It’s not surprising that 5e moved away from “recharge ” to “recharge 5–6”.