The struggle is real. One of the gyms near me has a bunch of autobelay devices that allow you to run laps. When ARCing started catching on, they had too many people (myself included) starting to do 20-30minute sessions which frequently means 10+ laps. That really ticked off a lot of “normal” gym members, and now that gym has a policy of 2 laps maximum per autobelay.
Ultimately, it seems like the best do it outside. Between Eldo and Red Rocks, Brad Gobright soloed thousands of pitches of 5.9 and under in just a few years before setting his crazy Nose record.
One expensive option is to get a treadwall if you can’t find access to one.
If all of those fail, it seems like your best bet is to double-down on skin care(the Anderson brothers book has quite a bit on that) and really execute the morning easy traversing sessions.