Question for guys familiar with 7075 and iron alloys

I’ve never worked with 7075 but do have a lot of experience with different steels and stainless steels and wanting to build a machine that is going to have basically a solid rectangular box 4x5x7 that will be sliding about 8” between steel plates on all side but will never contact the sliding surface as I will have wear plates protecting it. My question is would you be worried about using 7075 vs steel.

I’m building a tubing roller and this rectangular piece is the bending carriage that moves up and down. I’ve actually asked a question about this build before but being that I didn’t even know about 7075 then I ask this. I would use 4140 but can’t find a piece the correct size. Is someone that reads this knows where I can get a piece of 4140 4x5x7 or 4x6x7 or 4x6x6 for a decent price let me know please. I’ve found bigger pieces but would be a pain to machine in my machines and I seen a piece of 7075 for 90 bucks that is almost perfect size that I can machine and it got me thinking. Any help is welcome