Captain Reserve?
 

Could someone in the know please tell me the most junior captain line holder's seniority (DOH) systemwide? Looks to me like they've put the current deal together right for the max benefit of all. Still, I've never met a DEC I really wanted to trade places with. How much misery should one expect (for how long)?

Thanks in advance

That information would be outdated by the time I'd be done typing the message.
long story short, as a DEC you would be junior for about two years (until FOs hired with you start upgrading), but holding A line (vs a good line) is a function of having people below you. If you are the last DEC hired, life will suck. If you are on the front side of the wave, it'll be alright.
life sucked the most for the DECs that had seniority to go from a junior airplane to a 175 for better trips etc, but that was also the airplane everyone senior was upgrading into (figure 4ish years of reserve including the pandemic effect)
​​there were CRJ DECs holding a line within 3-4 months if not less, just based on how a bunch of them got put on it in a very tight time frame. The junior portion of that bunch, naturally, never saw a line.
all that being said, the current "DEC spot" is a OCL - ORD 175 CA - so the results will be mixed. On one hand, there's about 320ish people that might want to take the spot at some point and be senior to you (ORD 175 FOs, 145 CAs and FOs), on the other - not all of them will. There's 60ish people hired a month, anyone's guess how many of them are DEC eligible - figure some of them will become the junior captains.
All in all, expect 1.5-2 years of reserve. It will very likely be less than that, depending on where you are in the wave, but that's a good pessimistic number to keep in mind.

Right now, how long it would it take for a DEC/new hire forced upgrade to hold MIA 175?

Define dec/newhire forced upgrade

Well, if you get hired in wanting to be an FO but get forced to upgrade due to being junior and having over 1000 121. Really the same as being a DEC. Didn't the last award have forced upgrades on it?

So will PBS change any of the suck or is that just a marketing gimmick? I was interested in going to Envoy for the ord base. But with kids I’m worried about the schedule.

PBS is a computer algorithm that will optimize the schedules for the benefit of the company. Obviously, it will have to be set to respect whatever parameters may be in the contract, but this is already done with regular lines as well. Some people will be better at bidding using PBS and putting in the right options the right way into their bid, so they'll come out ahead, while others who aren't as good at programming PBS will come out behind. Everyone who has used both line bidding and PBS seems to like line bidding better. Think about it, the company isn't spending money on PBS to create better schedules for pilots, that's supposed to be the union's job. The first month or two everyone is probably going to be p1ssed off.

Its not only (or even mostly), about who is better at bidding. PBS will still only give you what your seniority will hold. The biggest difference is likely to be a huge reduction in OT. PBS won’t allow conflicts, so the only OT around will be sick calls, or the occasional Mil leave that gets submitted after bidding closes. QOL has way more to do with the efficiency of the trips. PBS will mostly just be less money in everyone’s pockets.

You have to learn what parameters actually ask PBS to do what you think think you're asking it for. There would be several parameters that would have to do with days off or time off, for example, and you had to use the right ones the right way to actually have a chance of getting what you thought you asked for. So if a more senior person bids for a certain day off improperly, and a more junior person bid for the same day off the right way, the junior guy would end up getting it. But yes, if both bids are done the exact same way then it has to respect seniority. The line bidding is more transparent to the pilots because everyone can see easily that if they didn't get the line they wanted that it went to more senior person and there is no question about if were any errors. PBS also allows the company to do credit pushes and load up everyone's schedules at the low end of the seniority list to keep the stuff that wouldn't have been awarded, out of OT, as you said. Either way, point is, PBS is for the benefit of the company, and not the pilots. If you don't like what you're being awarded now, it will probably get worse with PBS. It's marketed to younger people who haven't used both systems and think it's great to have everything automated, but there is a reason why PBS is a concession. People who have used both would take line bidding.

PBS sequences
 

PBS will not change the sequences at Envoy. There are some PBS systems that will build the sequences. Envoy is not going to use one of those. The sequences will be built by the same system currently building them. What MIGHT change some of them is the trip and duty rigs that are coming. Those rigs will either force them to improve the efficiency of trips, or at least still pay as if they are more efficient.