Looking just at the photos you posted, that outrigger, along with the undamaged one on the left side of the photo, support the "darco covered box" that I believe is the edge of the floor decking under the slide. The outriggers also support the weather stripping (slide seals) when the slide is in the travel position. I can't tell for sure, but those seals may also close off the slide when extended, preventing air from blowing into the trailer as well as preventing bugs/mice/ect from getting into the trailer.
As for the damaged outrigger, I'd cut it off at the "undamaged/rebendable" area, about 3 or 4 inches from the frame rail I beam. Then, I'd fabricate a similar outrigger, using the undamaged one at the other end of the slide assembly as a template. I'd drill holes in the "remaining part of the damaged outrigger" and bolt the new one to that location, trying to approximate the support to the seal strip and its assembly. If you "rip the entire damaged outrigger off the I beam, you're going to have "hell to pay" trying to reweld or drill and bolt a new one in place, and, depending on what's behing the I beam (like tanks, wiring, plumbing runs) it may be impossible to even get access to the back side of the outrigger location. I'd strongly urge you to use the existing outrigger (cut to serve as a mounting platform) to attach the new outrigger. That way, you can continue to support the slide seals and the "whatever else is attached to those outriggers" without having to drill into the I beam to attach something else.
If you don't have facilities to fabricate a replacement outrigger or if you can't find someone local to you that has a metal break (most auto body shops do) that can make one for you, here's a link to the Lippert store where a variety of outriggers are available for sale. While the exact size is not critical, you'll need to fabricate something that closely matches the undamaged existing outrigger on the other end of the slide. Here's the link:
https://store.lci1.com/catalogsearch...t/?q=outrigger
As for your DARCO on the slide bottom, from the photos you posted, there is some "beginning damage" to the DARCO. I copied your photo and circled the areas that look like they are beginning to wear in yellow. Take a careful look at those areas, there is some nylon fabric abrasion in the DARCO that looks like it's already worn through the outer plastic film. Here's the photo I marked up showing what I think is likely to be DARCO damage.....
Linear Mode
