Ended up adapting the Tools of Survival H re-launch combo for Level 1 Frank a bit with Dormammu to get a guaranteed Level 4 out of it…
j:h:, :d: :d::h: :s:, super-jump, j:m: j:m: j:h: j:qcf::h:, land, 1:)d:) :d::h: :s:, super-jump, j:m: j:m: j:h: j:qcf::l:, j:m: j:s:, land, wave-dash if needed, :a1: (Dark Hole), :qcf::s:, 2:)d::h:) :s:, super-jump, j:s:, j:d::h:, :qcf::s:, if in range :qcb::atk::atk:
1: Only do this move if starting the combo from a :d::h: or it will make the combo drop later on
2: Only do this move if you started the comb from at least :d::d::h: or the following :s: will not hit in time! Also, omit this move on small characters, as it will simply whiff and it is not required.
Does over 700k damage when you are in range for the super, so definitely worth it! Just be ready to wave-dash plenty to reach smaller characters fast enough.
Tested this out on the various character sizes, and other than one move noted, it works on all sizes, so go to town!
EDIT: Another combo to share! This time it is an instant over-head combo specific to Sentinel and Nemesis since part of it requires their rather fat hit-boxes (does not work on Hulk, sadly):
j:m: j:m: j:h:, land, :d: :h: :d::h:, :qcf::l:, :l: :h: :s:, super-jump, j:m:(2 hits) j:h: j:qcf::l:, j:s:, land, :qcf::h:, :s:, super-jump, j:s:, j:d::h:, :qcf::s:, :qcb::atk::atk:
Does over 900,000 damage at Level 5, so it will out-right kill Sentinel if you land the whole thing. At level 4 all you need is pretty much any DHC. Hope this will be helpful!