The design of the 5E Rogue class is not generous.
In games without feats, and where every adventure day is 8 encounters long, then maybe, just maybe, can the Rogue hold his own in the combat department.
But in games with feats the fighter get upwards of 35 or more damage a round, along with a host of other tricks. That's 10d6! There is no feat to meaningfully increase sneak attack damage.
And in games where the Sorcerer can cast a Fireball together with two Firebolts each combat (for something like 8d6+3d10+3d10+10 damage) the Rogue's so-called "alpha strike" looks just sad.
But the design is not only too stingy with damage. It is poor and counter-intuitive. There is no burst/nova capability. Correct play requires absolute system mastery, to gain two sneak attacks in as many rounds as humanly possible. The Assassinate ability is just mean to the Rogue player, enclosed in so many requirements it basically never happens in games where the party consensus is that solo raids are boring for the rest of the players; much more fun if everybody joins in to the combat simultaneously!
Sure the Rogue has its uses outside of combat, but let's be honest - D&D is a combat-heavy game, and there needs to be a straightforward way to build a Rogue that is competitive in combat.