While I agree that you shouldn't be able commit more salary than you have available, your example shows the problems that come with bidding on multiple FA at the same time. Problem is Manaea won't be the one that expires first necessarily. If I beat the original bid on Manaea after Glasnow is put up on day 2 it's now Glasnow that will expire first. Assume I valued both pitchers the same and there are no further bids on Glasnow. I'm now stuck with Manaea at god knows what final price and I never even got a chance to get Glasnow for as little as 8.1mil per year.
This is a risk of the bidding process. If you can't afford to bid on both, you have to decide who to offer and at what terms. Over paying is always a risk. I'm an Orioles fan, I know all about the dangers of over paying.
Also your example doesn't remove the need for rescinding. What if it was 2 pitchers that you could afford to put a bid on each. Let's say you win one of them. Wouldn't you now want to rescind the offer on the other if you only needed one pitcher?
You'd be stuck with them both.
I think if we have a rule stating that you can't have more money committed to free agency bids than you have available then most of the bidding problems would be solved. Yes, you might over pay by bidding early on a player. Yes you might end up with two players at a position rather than one. If these things happen, you messed up as a GM. One way to try and avoid these issues is to make the initial offer on players you want.
still much rather see us bid on only 1 at a time or a small group at a time so that someone could bid on all the players they'd like rather than having to choose.
I think having to choose is part of the strategy of free agency.
I'm just thinking out loud here and want to continue this discussion. We'll get to an agreement eventually.
Phil