Honestly, if Caleb Williams and Drake Maye are guaranteed to go 1-2 and neither the Bears or Commanders trade out of it, I probably would give up a 2nd or 3rd round pick for Fields and use the #3 pick on MHJ.
I like Jayden Daniels but it's risky. And this way, you still get a mobile QB and add a legit WR1 in MHJ. Tackle is still a need but it's a very deep draft for it, you can even get one in the 3rd round potentially. Keep Bourne, Henry and Elliot to go along with Douglas, Stevenson, etc. and I think you're a solid team that can grow with Mayo as HC and Fields the QB. Or even if Fields doesn't pan out, you can still build up the team and then either sign or draft one later on. The QB is important but you also need a stout O-Line + a few good weapons to help them (look at Houston, Green Bay, etc.)
I know people will mention Baker Mayfield, Kirk Cousins, etc. but Baker is probably staying in Tampa, Kirk Cousins + Kyler Murray make a ton (or will make a ton elsewhere) and outside of that it's the bridge QBs anyways like Jimmy G, Brissett, etc. No thanks. Fields is still young and intriguing. He definitely seemed to improve in the 2nd half of the previous season as well.