WC 2006: If you watched you remember Boulahrouz taking him out of the Netherlands game injured 33 minutes in, he wasn't 100% vs England. He didn't play vs Mexico and was subbed early vs Angola. So it was a pretty good WC for him when he wasn't injured.
WC 2010: Yes he wasn't good, Queirós was horrendous as a manager though and it's not a coincidence that with him Ronaldo had the worst spree in the portuguese shirt, his tactics made sure Ronaldo (or anyone else) got nothing out of the games.
WC 2014: He was injured. You can argue why did he play then but that's not his decision to make, obviously he wanted to play.
WC 2018: You didn't then watch the Spain game because Ronaldo was pretty damn good in all round play, he setup Guedes many times with his quick flicks and passes in the link up play in the beginning of counterattacks (we didn't have the ball much). Vs Morocco he was ok, still better than most of Portugal's midfielders and attackers except Moutinho. Against Iran even though he missed a penalty and didn't do much he was still better in midfield and attack than everyone bar Quaresma that was great. He was poor vs Uruguay yes. In short he was far from brilliant.
WC 2022: Was only good vs Uruguay. Was a sub in the 2 knockout games due to his reaction to being sub vs South Korea.
He never had a great World Cup, far from it, but if you look at the circumstances you can take some conclusions.
In 2006 we had the best team in these WCs and it shows, Ronaldo was pretty good even though he wasn't the only major figure in the national team. Lost tightly to France in the semi-final.
In 2010 everyone expected it to be bad. Queirós was horrendous and bitter towards everyone (continues to this day vs the Federation), he didn't call Moutinho that did a great season for no reason (this actually was a key trigger for Moutinho to turncloak and transfer to Porto as the captain of Sporting) and his tactics were horrible in general. Nani, our other star besides Ronaldo, got out of the squad in mysterious circumstances. Ultra defensive tactics vs Ivory Coast (0-0 draw) and vs Brazil (0-0 draw) and North Korea only folded because it was bad enough for us to break through. Against Spain yet another ultra defensive posture with the famous Ronaldo reaction to Queirós when he subbed off Hugo Almeida (that was actually threatening Spain's defence) to put another midfielder or defender (can't remember) - "Assim não vamos lá, Carlos" "We won't make it this way, Carlos". After the game another quote to show how things weren't good between them ("ask the manager" when he was asked something, maybe why we gave up attacking in this game, I don't fully remember. Also the quality of the national team had declined a lot since 2006.
In 2014 he was injured so it isn't surprising he wasn't good. The Federation had an horrendous preparation, with wrong cities chosen to prepare in Brazil, etc. The squad was lackluster and it shows when we struggled vs the USA and Ghana. We were eliminated basically because of Germany (this is just a fact I'm not making any conspiracy) - they had crushed us 4-0 in the first game with an early red card for Pepe and in the game vs the USA they knew they would eliminate us if they beat the USA marginally and we didn't crush Ghana. This ended up happening.
In 2018 we already discussed plenty, but as I said he was the reason we even got out of the group stage in the first place. Uruguay was tight but we didn't have any urgency. Our squad got much better since 2014. Santos should have left here.
In 2022 he was going through a terrible period and he has aged a lot, not surprising he didn't perform. Our squad is pretty damn amazing and Santos has its fault in how we did(n't) play.
That's why I said choosing World Cups to judge Ronaldo is cherry picking, just like choosing whatever competition to analyse Messi is also cherry picking for the bad or worst. They have been brilliant in all kinds of competitions and in Ronaldo's case he has shown that in games equally as hard as World Cup's (aka Euro or Champions League) he performed well. Therefore the argument that he didn't have good World Cups because he isnt good enough crumbles away. And let's not forget the special case of national teams, players can't move away from a squad and get better teamates the next year. In Ronaldo's case he only had good squads in 2004-2006 and from 2018-present while in Messi's case he had good squads until 2018, I would say the current world champion argentinian national team in theory (just looking at the players) is the worst in 20 years