Payouts and LP got nerfed repeatedly over the years for L4 missions. CCP did add burner missions but they need specialized ships and fittings to run.
If you can fly a nightmare though i highly recommend try running incursions as it’s one of the main ships that’s used. You can make 100 to 200+ mill per hour running incursions plus concord LP on top. Concord LP is the best LP as it can be used at nearly all the LP stores except for the pirate ones.
https://wiki.eveuniversity.org/Incursions
For brand newbro/alpha and shield tanking try warp to me.
join in game chat channel “Warp To Me Incursions”
If you want to fly armor and make the big isk try The Ditanian Fleet.
join in game chat channel “TDF-Official”
Both communities are very good at what they do and will help you make plenty of isk.
Note: for channel names ignore quotation marks.