I have Trek Marlin 5, Today I broke rear hub axle. unfortunately, shops are closed nearby, because of COVID-19, I only have solid hub axle. Is it okay to use solid axle instead of quick release?
3If the axle fits into the hub nothing speaks against using it. Just remember that you need an adequate wrench in your road tool-kit so that you can remove the wheel in case of a puncture on the road.– CarelMar 22, 2020 at 8:29
Yes, QR axles can be replaced at will with solid axles for all standard axle hubs. (Standard axle means a hub that can accept a generic third party axle. Many hubs are not.)
Be mindful that the common toothed type axle nuts are good at tearing up aluminum and carbon frames. Use washers and grease the threads.