The "safety!" argument against RTR is disingenuous. Just as the "landfills!" argument in favor of RTR is also disingenuous.
Nobody on either side actually believes those things (regardless of how passionately they claim to). They are both fallacious appeals to get disinterested people emotionally wrapped up in the topic.
RE: safety, people getting hurt trying to repair stuff happens already and will still happen post-regulation. Right to repair will not result in more injuries.
RE: landfills, most people don't throw stuff away because it breaks. They throw things away because newer models are more powerful, faster, smaller, more efficient, or aesthetically "cool." Right to repair will not result in less landfills.