If you're passively waiting for resumes to walk themselves over to your recruiters then the candidates you'd like to source are probably instead talking to the

If you're passively waiting for resumes to walk themselves over to your recruiters then the candidates you'd like to source are probably instead talking to the engineering managers who took the time to introduce themselves and their firms. The candidate profile you're looking for can write their own ticket; if you don't have a compelling answer to why that ticket should say "I'd love to work at a fairly typical run-of-the-mill mid-size enterprise software vendor" you need to spend some shoeleather convincing people of that. I'd also recommend radically more effort in producing artifacts which some would classify as "top of funnel" or "engineering brand" so that you have some hook to start conversations with and some differentiation with all the other prospective employers of senior engineers.