If we can upgrade on him, which we should be aiming for, then the next logical step isn’t to get rid of him altogether, but to drop him down one in the pecking order and use him to replace Lyall/Taylor/Robertson/Crawford in the role of backup midfielder.
Using him in that role would be far easier and more beneficial than shopping around for someone who’s happy to sign on those terms. As they’d barely play, it would likely be someone who’s completely done or has no experience. Also, after a one year extension he’d still only be 35 at the end of that contract, it’s hardly Kirk Broadfoot.