[tubby12345]

it depends on what your skillset really is and what areas you're interested in for your phd.

pure theory (finite automata, complexity, computational geometry, optimization)? yea you're probably locked out by virtue of competing against students that have the relevant theory fresher in their heads. note i didn't list ML there because i personally don't consider ML theory heavy (no matter what the wannbes will claim wrt to TDA or whatever).

basically in any other area, if you have true hard skills (e.g., deep systems knowledge, networks, graphics) then you're competitive as long as you have a decent ugrad GPA and can get a decent GRE and some decent letters of rec. the path looks like reaching out to a potential advisor and starting a conversation with them about whatever research of theirs you find interesting.

[tasogare]

Yep. In my lab two people are doing a PhD while having left university for awhile and while still doing their job (teaching English).