Attention...
For any question about "how do I get speed / flexibility / seniority / QOL as a new hire, let me summarize the past 10,000 posts on this subject:
Bid the 737 to the base of your choice.
Or a 737 to the closest base... since you can lateral as soon as a slot opens up. Which won't be long.
And if you're DYING to fly the 757, just bid the Guppy anyways... do it for 1-23 months... and bid to the 757 with NO additional freeze, once you have a modicum of SA on what life at UAL is like as a Guppy FO.
Or just bid the biggest thing you can get anywhere and expect to sit reserve for a couple of years.
Your call.
But honestly... does it take this many posts over the past 5 years to understand this?
p.s. "I hate going back to TK" is a common excuse to avoid doing more training. Keep in mind that when you go from the 737 to the 757, it's about 20 days over the course of 4 weeks. It's not 4 months. And you go home on the "weekends" if you want. It's not a hardship tour.