That might be part of your problem. The thing about bee pheromones is that they are volatile. They have to be to spread through the hive. But that also means that they evaporate much faster from large, flat surfaces. Foundation is a large, flat surface. A big block of beeswax may keep its wonderful smell, but foundation loses it over the years.
You could certainly try painting some melted burr comb onto the foundation in the Ross rounds, but I still think you are probably too late for this year. If you decide to do that, I would do it just before you put the super on the hive next spring. That would also give you some time to collect some burr comb in the remaining season (freeze it to save the pheromones) and then you have some to use next year.
An easier way might to be to buy some fresh foundation next year. For comb honey, I really like Kelley Bees thin foundation. I would buy it in about February next year for next season. Here is a link:
https://www.kelleybees.com/foundation-for-medium-frames-s-twnw.html
https://www.kelleybees.com/foundation-for-round-section-frames.html
You could buy it now and freeze it, but I find that freezing makes foundation brittle, even after it warms up, so I don’t do that.