The advantage that Mahomes gives you is that he is a set it and forget it top 5 guy week in and week out with a greater than 50% change of being the top QB each week. There is value in that even if you can find other QB's that "can" score similarly at times.I think that’s too much for Mahomes in a 1 QB league. There’s a ton of QBs who are cheap that can put up numbers close to him.
I think two 1st's and two 2nd's is a bit on the high end but depending on your team I have no problem giving that up for the security that Mahomes provides.
Just felt like for this year (and maybe the foreseeable future) that Beckham is worth taking the shot on here, particularly with that pick being two years out.