I had read this and I (kind of) get this, but the formulation is very vague and unspecific, probably on purpose.

The core of the question is what priority order actually applies and I am under the impression that this has become completely intransparent.

I understood that the new system was categorically „bids first“, being the amount the crucial aspect, probably before status and time of placing the bid.

Now it seems something rather along the lines of WHO is bidding. Hence, is a USD 50.00 bid from a BS worth more than USD 100.00 from a B? And is a high bid from a non-status passenger worth more than a BS coupon? And how are upgrades against miles treated?

I‘d love someone to illustrate what the priorities are.

The only thing I know, is that the upgrade list with coupons (the only one accessible to the passenger) does not really reflect your chances on scoring the upgrade, because other types of bidders interfere and may have priority.