How do I raise concerns about workload and pay without throwing a poorly performing colleague under the bus

How do I raise concerns about workload and pay without throwing a poorly performing colleague under the bus I work remotely for a small IT company with around 20 employees. The development team consists of roughly ten mostly mid-to-senior developers, one junior developer and several testers. We meet in person about twice a year. I joined less than 12 months ago and have become one of the more productive members of the team. I have taken on some fairly complex work and introduced changes that reduced our reliance on expensive third-party APIs, resulting in meaningful cost savings. My annual review is coming up, and I already feel that my experience, output and impact justify a pay rise. However, there is another issue that is beginning to affect my motivation. One developer has been with the company for at least five or six years but consistently produces very little work, and what he does produce is often of a poor standard. He is regularly assigned simple BAU tickets that another developer could complete in 10-15 minutes, but he may spend most of a day on them and then require another day to address basic code review feedback. Because he completes lots of small tickets, his output might look reasonable to someone who does not understand their complexity. In reality, even our junior developer appears to produce considerably more useful work, despite presumably being paid much less. When this developer receives anything moderately difficult, he will often get stuck and ask someone else to guide him through most of the solution over a video call. When I first joined, I was happy to help because I wanted to support the team and demonstrate that I was collaborative. Over time, it has started to feel less like mentoring and more like completing his work for him, particularly as he often seems to have made little effort to investigate the problem himself. A recent PR made the problem particularly obvious. It contained completely irrelevant emoji-related code, apparently generated by an AI coding tool. The ticket had nothing to do with emojis, so it was clear that the output had barely been reviewed or tested before the PR was opened. The difficult part is that he is genuinely a nice person. We get on well outside the day-to-day work, and I do not want to damage that relationship or make this personal. My concern is entirely about his contribution as a teammate. The company has a relatively flat structure, and although I have not seen anyone else's salary, I suspect we earn roughly the same amount despite the difference in experience, responsibility and output. That is increasingly making me question why I am pushing myself so hard while somebody else can contribute very little without any apparent consequences. Our CEO is approachable but primarily sales-focused and does not get involved much in project management. The project manager handles ticket allocation and gets on particularly well with this developer. I like and respect the PM, but it seems clear that the weaker developer is deliberately given simple work while more capable developers are repeatedly assigned the difficult tasks. This does not appear to be temporary. I have looked through several years of his previous PRs, and the same pattern seems to have existed from the beginning. As far as I can tell, nobody has formally raised his performance with management. The company has a very relaxed culture, with limited performance management or accountability, so problems like this appear to be tolerated rather than addressed. There sometimes seems to be little incentive for people to challenge poor performance, provided everyone continues completing enough work to keep things moving. This may explain why the situation has continued for several years without intervention. For my annual review, I intend to focus on my own results, responsibilities and the value I have delivered rather than directly comparing myself with another employee. However, the unequal workload and the expectation that stronger developers will compensate for weaker ones are starting to become a genuine concern. How should I approach this? Should I raise the wider workload problem during my review, or keep the discussion strictly focused on my own performance and salary? Also, how can I set reasonable boundaries when he asks me to effectively complete difficult tickets for him without becoming unhelpful or damaging our working relationship? Constructive advice would be appreciated.