A lot of times you can look under the bottom rung on the ladder and find a sticker stating max capacity, on our ML 2109S it is marked as 300 lbs.
I fabricated and installed a rear receiver hitch on our trailer, I'd never trust the ladder for carrying a bike personally. All the 2020+ Mini Lites come with a factory receiver hitch rated for I believe 300 lbs, but since ours was an early 2020 model we didn't get one with ours....
Even if the weight rating on the ladder says it would handle it, that doesn't take into consideration the dynamic forces applied from bouncing down the road and the fact that the bike is cantilevered off the ladder, with increases the moment loads.
Post #475 in the link below shows the receiver hitch I made for a bike rack, we would only ever carry one bike on it since our other two bikes go up front on the factory hitch rack, but I have no worries about hitch capacity and I've removed the hinge pins from everywhere possible on the actual bike rack and replaced them with Grade 8 bolts w/ lock nuts. If you don't have access to a welder I'm sure a welding shop can built you one.
I'm pretty sure there's also some bolt-in options out there that only require a few holes be drilled in the frame rails. I didn't go this route because they hang down a little and I was trying to maintain maximum ground clearance at the back of our trailer.
https://www.forestriverforums.com/fo...184896-24.html