Starlord with 3 extra covers or Venom with 2 extra covers?
None of the above. Save for someone not in the trash tier.
Until Starlord gets an Ironman 40 level buff he’s not worth putting ISO into. I have a champed Venom and I like him, but he’s only usable PVP when buffed. His black is only useful in PVE and can only hurt you PVP, since it only really counters Falcap, who isn’t widely used. If you have to choose between the two I’d go Venom, but only if you’ve got all the usable 4s champed and have been really unlucky with 5 pulls.
no idea what your roster is. if this is your first 4* champ, I agree with stoch - save it and wait for a solid character to start with. if you have 15 4* champs, including all the ‘top’ guys, I’d personally go venom. starlord is interesting to tinker with when he’s essential, but is never something I build around. boosted venom can at least deal some damage that isn’t tied to CDs.
Maybe I’m contrarian, but, of the two, I’d do Star-Lord first (I really want to mess around with his yellow, and need him to be much higher level to do so). I would agree, though, that you shouldn’t do either unless you have a ton of 4* champions already (I have 16, and neither is yet on my radar).