Of course you can always find cap space. But finding that cap space has consequences. Take a look at the math and details here:
https://steelersdepot.com/2021/05/ad...with-steelers/. Say what you all will about Steelers Depot and Dave Bryan, but he usually gets the cap stuff nailed down. Here it walks through how the team has basically zero dollars to spend (ok. a bit more...but certainly not $5-8 million):
https://steelersdepot.com/2021/05/st...okie-minicamp/
So Moses costs you Chuks or an equivalent roughly $3 million salary. So Vince Williams? Derek Watt? Someone would have to go.
Currently the team is spending under $6 million on both their projected starting tackles:
https://www.spotrac.com/nfl/pittsburgh-steelers/cap/#
So what does Moses do that is TWICE to THREE times as good as either Banner or Chuks? Because that is decision. Pay Moses 2+x's your current OTs and turn around and cut one of them.
Anytime a team cuts a guy because of salary and the ability to sign/draft younger and cheaper players as replacements mean that they don't think the player is all that good.
Finally, none of Moses, Banner, or Chuks is a "proven" LT. But we have training camp for Banner and the 2020 season for Chuks to say that they can play adequate RT. For 50% the cost of Moses. Say you sign Moses, you gotta gamble then that one of the three (Banner, Chuks, Moses) can step-up and play LT. Most likely you are going to have to have it be one of two guys because you cut Banner or Chuks to get Moses on the roster. So what did you gain there? Media plaudits for landing an experienced OT? Remember, Tomlin and Co think Banner is a top-end OT in the NFL. They also drafted Chuks to be the LT after AV. Are they right, I don't know and neither do they...but it is a gamble anyways -- so why not take the cheaper gamble?
Like I said earlier...let's not sign the pricier veteran RT (this is not like when Flozell was signed) and play weird roster games to make it work. Look around for the next AV, Beachum, Fred Johnson, Ramon Foster, or Banner. Young, cheap, over-looked and with massive upside. That's where this team has had success in the past with offensive line depth signings. Why not go to that well again?
Save what little pennies they may have for a DB or OLB signing. Those two positions are typically much harder to find UDFA's and younger players that can step in and perform.